Research Articles

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Genome-wide association analysis identifies resistance loci for bacterial blight in diverse East African rice germplasm
(Academic Journals, 2023-07-31) Okello, Moses; Mildred, Ochwo S.; Lamo, Jimmy; Onaga, Geoffrey; Odong, Thomas L.; Tusiime, Geoffrey; Tukamuhabwa, Phinehas; Mukasa, Settumba B.; Wasswa, Peter; Ogwal, Jonathan; Oliva, Ricardo
Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of rice bacterial blight disease has been extensively characterized, and loci against different races identified. Many rice cultivars have been developed and utilized to combat the disease, however, due to the rapid evolution of Xoo, several resistances have broken down. The continuous challenge of ever-evolving Xoo and the breakdown of resistance in cultivated rice varieties make it even more important to discover new loci to enable sustainable durable deployment of broad-spectrum resistance genes in elite breeding lines. African germplasm can be exploited as reservoirs of useful genetic variation for bacterial blight (BB) resistance. This study was conducted to identify loci associated with BB resistance and new genetic donors for the breeding program. To identify candidate sources of resistance for advancing breeding, four virulent strains of Xoo (PXO99, MAI1, BAI3, and Xoo3-1) were used to screen 78 East African accessions by genome-wide association studies. The diverse accessions' core genetic base exhibited high resistance to the Xoo strains. 50.63% of the accessions were highly resistant to the Philippines strain PX099, while 20.25% were highly susceptible to the virulent West African strain MAI1. Two novel resistant loci significantly associated hotspots were identified using 1901 SNPs. The two hits were located on chromosome 12 (Xa25) and Chr. 6 (Xa7, Xa27, Xa33). Novel loci were identified that gives a useful basis for more investigation and a wide core genetic pool of high resistance for broad-spectrum resistance for genetic improvement.
Genome-wide association mapping in rice MAGIC indica panel detects QTLs and genes for broad-spectrum resistance breeding against African bacterial blight
(ORYZA-An International Journal of Rice, 2024-03-30) Okello, Moses; Ssemakula, Mildred Ochwo; Lamo, Jimmy; Onaga, Geoffrey; Odong, Thomas L; Geoffrey, Tusiime; Tukamuhabwa, Phinehas; Mukasa, Settumba B; Wasswa, Peter; Ogwal, Jonathan; Oliva, Ricardo
Rice (Oryza sativa) bacterial blight (BB) is a direct threat to production in Africa. The extent of damage on the continent is not known. We conducted a genome-wide association study (GWAS) to seek out Quantitative trait loci (QTL) that confer the broad-spectrum resistance (BSR) to rice Xanthomonas oryzae pv. oryzae in the rice Multiparent advanced generation intercross (MAGIC) population. The diverse genetic composition and high levels of recombination, are potential resources for the identification of QTL for BSR. Dealing with the everevolving Xoo requires identification of novel R gene and resistance quantitative trait loci (QTL). We conducted a genome-wide association study (GWAS) using 250 rice MAGIC indica panel to evaluate for resistance to three Xoo strains from Cote D'Ivoire, namely XooCIkor, XooCIgag and XooCIcii2 which are prevalent highly virulent pathotypes. Using the 3 K RG 4.8mio filtered SNP Dataset, a total of 3 QTL associated with BB resistance on chromosome 9, 6 and 5 were identified. The results of the GWAS identified novel loci that gives useful insight for more investigation and also validated known genes underlying resistance to virulent African strains of BB. Genetic donors identified in this will help plant breeders in improving and broadening resistance to BB.
Boric acid recovery from wastewater by chromatographic separation and mathematical modeling
(Elsevier, 2024-03-04) Kole, Zehra; Ocal, Zehra Betul; Omwene, Philip Isaac; Soydemir, Gulfem; Keskinler, Bulent; Karagunduz, Ahmet
The new approaches in industrial wastewater management underscores the importance of reclaiming valuable materials. Within the boron industry, the generation of substantial wastewater containing preliminary boron species is a significant concern. This study focuses on recovering boric acid from boron production wastewater, addressing the challenge of separating impurities like sulfate, calcium, and magnesium. The methodology adopts chromatographic separation using a cation exchange resin in two forms: (1) Finex CS10GC cation exchanger in Na+ form and (2) Finex CS10GC cation exchanger in Ca2+/Mg2+ form. Notably, the Finex CS10GC ion exchanger in Na+ form achieves a separation efficiency of 95.5 % at a flow rate of 5 mL/min with a 0.20 bed volume (BV) loading. In contrast, the Ca2+/Mg2+ loaded resin achieves a separation efficiency of 23.3 % at the same flow rate. As the boron loading rate decreases to 10 %, the separation efficiency increases to 42.6 %. The flow rate also plays a crucial role, as an increase corresponds to a decrease in separation efficiency. Notably, the Finex CS10GC ion exchanger in Na+ form consistently exhibits superior separation efficiency and band resolution. A mathematical model is introduced to simulate the effective separation of boric acid from other impurities. The quality of the recovered boric acid conforms to the standard grade (Merck KGaA), exhibiting a purity level within the range of 99.5–100 %, suggesting substantial economic value. The proposed recovery process contributes significantly to environmental preservation by mitigating waste discharge, exemplifying a noteworthy commitment to resource conservation.
Histological features of the gastrointestinal tract of elongate tigerfish, Hydrocynus forskahlii (Cuvier, 1819), from Lake Albert
(Springer Nature, 2024-05-10) Kasozi, Nasser; Iwe, Gerald D.; Langi, Sandra; Namulawa, Victoria T.; Walakira, John
The tigerfsh (Hydrocynus forskahlii) is an important food fsh in diferent regions of Africa. As such, interest in its performance and nutritional requirements as a potential candidate for aquaculture is increasing. Characterization of the morpho-histological features and functions of the gut provides valuable insights into the feeding physiology and digestive system of fsh species. An investigation of the morpho-histological features of the gastrointestinal tract of H. forskahlii captured from Lake Albert was conducted over an eight-month period. The digestive tract of H. forskahlii is characterised by a short oesophagus, well-developed and distensible stomach and moderately long intestine. The oesophagus had a higher abundance of mucous-secreting goblet cells compared to other digestive tract tissues. The stomach had a bag-like shape for swallowing large prey and was distinguishable into the cardiac, fundic and pyloric regions. Both the cardiac and fundic regions of the stomach had numerous gastric glands, whereas the pyloric region had large compound folds consisting of pseudo-stratifed columnar epithelium. Many goblet cells were also observed in the mid and posterior regions of the intestine. The relative length of the gut of the H. forskahlii was 1.27±0.03 cm, and it had a total of 20–22 pyloric caeca. The liver was observed to be divided in lobules by a central vein contained within connective sheets. Irregular cords of hepatocytes were also visible throughout the parenchyma.The histological features of the H.forskahlii gut observed in the present study are consistent with those of carnivorous and omnivorous fsh.
Nutritional requirements and effect of culture conditions on the performance of the African catfish (Clarias gariepinus): a review
(Taylor & Francis, 2024-01-23) Langi, Sandra; Maulu, Sahya; Hasimuna, Oliver J.; Kapula, Veronica Kaleinasho; Tjipute, Martin
Aquaculture is crucial for global food and nutrition security due to the inability of wild harvests to meet increasing demand. Africa’s contribution to aquaculture is generally low, despite its potential for economic development, food security, and reduced unemployment. The study focuses on the African catfish (Clarias gariepinus) a freshwater fish species that is widely farmed for food in Africa and other parts of the world. Proper nutrition is essential for the growth and development of the fish, and understanding their nutritional requirements is critical for producing healthy and high-quality fish. This review article provides an overview of the knowledge on the nutritional requirement of the African catfish, including protein, lipids, carbohydrates, vitamins, minerals, and amino acids. The recommended protein content for juvenile fish is between 40 and 50% and for adult fish is between 30 and 40%. Based on the reviewed studies, the recommended amount of methionine in C. gariepinus diets ranges from 18.7 to 29.7 g/kg of protein while the lysine requirement ranges from 44.9 to 62.2 g/kg protein). The recommended lipid content in the diet is between 5–15% for juvenile fish and 5–10% for adult fish. The African catfish requires a low-carbohydrate diet, with recommended carbohydrate content between 26 and 32%. They require a variety of vitamins, including vitamin A, vitamin D, vitamin E, and vitamin C, as well as minerals, such as calcium, phosphorus, and potassium. Clarias gariepinus also require a variety of essential and non-essential amino acids. Besides the nutritional requirements, culture conditions also have a significant effect on the feed performance. The recommended conditions include temperature ranging from 28 to 32 °C, Light intensity of 150 Lx, 12D:12L photoperiod, and stocking density in earthen of 7 fish m−3. Overall, understanding the nutritional requirements of C. gariepinus is crucial for the successful fish farming and sustainable aquaculture. Information in this review will be built to further guide the development of feeds for C. gariepinus.
Integration of probiotics in aquaponic systems: an emerging alternative approach
(Springer Nature, 2023-08-28) Kasozi, Nasser; Iwe, Gerald Degu; Walakira, John; Langi, Sandra
The increasing demand on water resources, reduced land for agriculture, and concerns over food and nutrition security have prompted the evolution of innovative and complex food production systems. In this context, efficient and sustainable food production systems such as aquaponics are viewed as an important and environmentally friendly technology for adaptation under resource-limited environments. Producing food in soilless systems is a promising strategy, as this method utilizes significantly less water than traditional agriculture. However, optimizing growing conditions to enhance crop and fish yields in aquaponics is frequently ambiguous and is often not economically feasible. One of the strategies to improve plant yields and supply of nutrients in aquaponics is the application of probiotics. With this strategy, the crop yields in aquaponics are improved via a variety of mechanisms, including nitrogen fixation, solubilization of mineral nutrients, organic matter mineralization, plant hormone modulation, and biocontrol. As a result, incorporating probiotics in aquaponic systems is a strategy for mitigating environmental effects and advancing sustainable agriculture. This review paper provides the current knowledge of the use of probiotics in aquaponics. Suggestions for further studies on the effects of probiotics in aquaponic systems are proposed. Through literature review, integrating probiotics into aquaponic systems has the potential to improve nutrient supply, modulation of water quality parameters, and microbial communities, which are key processes in enhancing the productivity of aquaponic systems.
Effect of phosphorus-based fertilizer on groundnut yield and incidence of groundnut rosette disease in West Nile Region of Uganda
(African Journals Online, 2023) Abaca, Alex; Odama, Emmanuel; Komakech, Alfred; Kassim, Sadik; Walakira, John K.
The objective of this study was to establish the effects of Di-ammonium phosphate (DAP) fertilizer micro-dosing on yields and the incidence of groundnut rosette disease (GRD) on five groundnut varieties in West Nile region of Uganda. The field experimental design used in this study was 5x2 factorial laid in a randomized complete block design (RCBD) with three replicates per location across 6 locations. The results indicated that there were significant (p = 0.05) differences in groundnuts yields across locations and varieties (0.554 – 1.742 tons per hectare) with or without micro-dosing with DAP fertilizer. The effects of DAP fertilizer micro-dosing in groundnut production were twofold: increase in yields across locations from 427.27kg/acre with no micro-dosing to 525.73kg/acre with micro-dosing (23.04% increment) and varieties from 420.46kg/acre with no micro-dosing to 529.71kg/acre with micro-dosing (13.77% increment); and a reduction of groundnut rosette virus disease incidence across locations from 15.13% with no micro-dosing to 11.20 with micro-dosing (27.76% reduction) and on varieties from 15.08% with no micro-dosing to 11.82% with micro-dosing (34.62% reduction). This is the first report of a prospective DAP fertilizer micro-dosing alongside other improved agronomic practices which can be integrated fully into groundnut production in West Nile region of Uganda. To manage yields and GRD incidences, micro-dosing of crops should be taken as a climate smart technology as identified by Food and Agricultural Organization.
Investigating the removal efficiency of different textile dye classes from wastewater by electrocoagulation using aluminum electrodes
(Springer Nature, 2023-02-23) Omwene, Philip Isaac; Can, Orhan Taner; Oz, Ufuk Muhammed; Keyikoglu, Ramazan
Textile production is one of the largest sectors in the manufacturing industry; however, the textile dyeing process produces a voluminous amount of highly colored wastewater. The dyes used are organic compounds of different dye classes that are stable in an aquatic environment with low decomposition rates. This study investigated the removal efficiency of five textile dyes of different dye classes (Disperse Orange 30, Acid Blue 324, Basic Yellow 28, Reactive Black 5, Vat Brown 1) from wastewater by electrocoagulation (EC) process that was equipped with aluminum electrodes. EC process achieved 91.98, 98.13, 47.46, 92.55, and 82.60% removal efficiencies for AB324, BY28, VBI, and RB5, respectively, at a current density of 0.83 mA/cm2. The energy consumption for dyestuff removal was in the following order: DO30 < VB1 < RB5 < AB324 < BY28. The total operating cost per kilogram of dyestuff removed in 15 min at 0.0502 mA/cm2 was determined as 0.250, 0.274, 0.550, 0.647, and 0.764 $/kg for DO30, VB1, RB5, AB324, and BY28, respectively. The removal mechanism was well fitted to the pseudo-first-order kinetic model with R2 above 0.94 for AB324, BY28, and RB5 dyes. However, the removals for DO30 and VBI dyes were exponential and neither fitted the first-order kinetic nor second-order kinetic model. The overall removal trend was as follows: DO30 > VB1 > AB324 > RB5 > BY28. Therefore, the use of dyes that can easily be removed from wastewater should be encouraged to preserve the quality of water in the receiving environments and to reduce the cost of wastewater treatment.
Conforming to agricultural water reuse criteria: wastewater recovery by electrooxidation integrated with nanofiltration/reverse osmosis
(Springer Nature, 2023-02-21) Çiftçioğlu‑Gözüaçık, Bengisu; Omwene, Philip Isaac; Ergenekon, Sinem Merve; Karagunduz, Ahmet; Keskinler, Bülent
In this study, two membrane configurations were investigated for water recovery in order to determine the potential for quality irrigation water production from alkaloid industry wastewater. In the first configuration, electrooxidation (EO) was used as a pretreatment before the NF90/BW30 units. In the second configuration, a single-pass, two-stage system consisting of NF4 and NF90/BW30 membranes was applied by replacing the EO unit with NF4. The initial and final fluxes in the single-pass two-stage system with NF4 and NF90 were calculated as 10.2 Lm− 2h− 1 and 5.4 Lm− 2h− 1, respectively. Initial fluxes for the NF4 + BW30 and EO + BW30 combinations were 9.4 Lm− 2h− 1 and 3.2 Lm− 2h− 1, respectively. Increasing the current density from 256 to 768 A/m2 caused the specific energy consumption (SEC) to increase from 10.26 to 15.84 kWh/kg COD. Scanning Electron Microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) were used for membrane autopsies. Compliance with the criteria for agricultural reuse of recovered water was evaluated based on four key parameters: salinity, pathogens, nutrients, and heavy metals. The combination of electrooxidation and membrane treatments enabled simultaneous disinfection, reduction of salinity and heavy metals to comparable agricultural water reuse criteria.
Novel chromatographic purification of succinic acid from whey fermentation broth by anionic exchange resins
(Springer Nature, 2022-11-09) Omwene, Philip Isaac; Öcal, Zehra Betül; Yağcıoğlu, Meltem; Karagündüz, Ahmet; Keskinler, Bülent
Replacement of the petroleum-based refineries with the biorefinery is regarded as an essential step towards a “zero” waste (circular) economy. Biobased succinic acid (SA) is listed by the United States Department of Energy among the top ten chemicals with the potential to replace chemicals from petroleum synthesis with renewable sources. Purification of biobased succinic acid from fermentation by-products such as alcohols, formic acid, acetic acid and lactic is a major drawback of fermentative SA production. This study addresses this issue through a novel chromatographic separation using three distinct anionic resins: Amberlite IRA958 Cl (strong base anion exchange resin), Amberlite HPR 900 OH (strong base anion exchange resin) and Amberlyst A21 (week base anion exchange resin). The influence of process variables such as flow rate (0.18 BV/h, 0.42 BV/h and 0.84 BV/h), eluent concentration (1%, 5% and 10% HCl) and temperature (20, 30 and 40 °C) were investigated. The results indicated SA separation efficiency of 76.1%, 69.3% and 81.2% for Amberlyst A21, Amberlite HPR 900 OH and Amberlite IRA958 Cl, respectively. As the regenerant HCl concentration increased from 1 to 10%, calculated succinic acid separation efficiencies decreased from 80.3 to 70.7%. Notably, as the regenerant strength increased from 1 to 10%, the total amount of organic acids desorbed from the resin sharply increased. At operation temperatures of 20, 30 and 40 °C, SA separation efficacies were 81.2%, 73.9% and 76.4%, respectively. The insights from this study will be of great value in design of chromatographic separation systems for organic acids.
Provisional classification of wild edible fruits based on their nutrient profiles
(Acta Scientific, 2022-12-07) Omujal, Francis; Ochan, Peter; Okullo, Paul; Ogwang, Patrick E; Okia, Clement Akais; Natukunda, Sheilla; Olupot, William
Nutritional analyses of food have mainly focused on determining the nutritional composition. Few concentrate on their nutritional value. This study provisionally classified ten wild edible fruits (WEF) growing in the Teso sub region in eastern Uganda by their nutritional value. Fruit pulps of Carissa spinarum, Saba comorensis, Sclerocarya birrea. Flacourtia indica, Vitex doniana, Strychnos spinosa Ximenia americana, Vangueria infausta, Vitellaria paradoxa and Physalis minima were analyzed for proximate and mineral composition, and their recommended dietary allowance (RDA) per 100g calculated. Hierarchical Cluster Analysis (HLA), Principal Components Analysis (PCA) and Canonical Discriminant Analysis (CDA) were used to classify the fruits based on their nutrient compositions. Nutrient density profiling was used to evaluate the nutritional value using the Nutrient Food Index (NFI). The HLA returned two and three clusters at linkage distances of <25 and 15 respectively, showing that these clusters were nutritionally distinct from each other. The PCA returned five components which accounted for 86.27% of the variability in the nutritional composition. The variability in Principle Component I was explained primarily by differences in moisture, total energy and total carbohydrates and that in Principle Component 2 mainly by dissimilarities in amounts of Zn and Fe. Canonical Discriminant Analysis (CDA) generated three Canonical Discriminant Functions (CDF), the first of which explained 99.2% of the total variation of the clusters with total carbohydrate and potassium content as the major contributors (Wilks’ lambda: Λ = 0.173 and 0.041 for carbohydrates and potassium respectively). The nutrient density profiles had F. indica and P. minima as the top-ranked with their overall nutritional values largely contributed by protein, potassium and dietary fibre. These results suggest that classification of WEF based on nutritional composition is possible, and these could be used in their promotion among communities in public health and nutrition education.
Replacement of fishmeal using poultry-based protein sources in feeds for pikeperch (Sander lucioperca, Linnaeus, 1758) during grow out phase
(Springer Nature, 2022-09-05) Langi, Sandra; Panana, Edson; Alloo, Ceder; Van Stappen, Gilbert; Meeus, Wouter
A 61-day growth experiment was carried out to evaluate the potential of a poultry-based protein (PBP) comprising of feather meal (FeM) and poultry meat and bone meal (PMBM), as a fishmeal (FM) substitute in diets of juvenile pikeperch (Sander lucioperca, L.). Pikeperch (initial body weight 113.12 g) were randomly distributed in groups of 250 fish in twelve 1.8 m3 circular recirculating aquaculture system (RAS) tanks, and fed four isonitrogenous (52% crude protein), isolipidic (17% crude lipid), and isocaloric (21.80 KJ/g energy) experimental diets. The feeds contained FM as the primary protein source (PBP0) or PBP replacing 20 (PBP20), 40 (PBP40), or 60% (PBP60) of the FM. Based on appetite and calculated uneaten feed, the feeding rate was initially set at 1.5% and subsequently reduced to 1% of the total tank biomass towards the end of the study. At the end of the experiment, the average feed intake ranged from 1.93 to 2.00 g/fish/day (p > 0.05). No adverse effects on growth and feed efficiency were observed in fish fed diets PBP0, PBP20, and PBP40. Particularly, the final body weight (FBW) (248.73, 240.11 g), feed conversion ratio (FCR) (0.86, 0.91), specific growth rate (SGR) (1.29, 1.35%/day), and protein efficiency ratio (PER) (2.20, 2.12) of fish fed PBP20 and PBP40 were not significantly different from the control PBP0 whose values ranged from 248.11 g, 0.89, 1.27%/day, and 2.18, respectively (p > 0.05). In all treatments, the condition factor (k) (1.31 to 1.33), hepatosomatic index (HSI) (2.35 to 2.70%), visceral somatic index (VSI) (6.87 to 7.19%), and whole-body composition of crude protein (57.77–58.28%) and crude lipid (23.85–26.85%) were not significantly influenced by the dietary PBP inclusion level (p > 0.05). However, whole-body ash content was significantly higher in PBP60 (14.66%) compared to the other treatments (12.57–14.43%) (p < 0.05). Based on the results from this study, up to 40% of FM can be replaced by PBP in diets for pikeperch juveniles without compromising growth performance and feed utilization.
Recent advances in the utilization of insects as an ingredient in aquafeeds:
(Elsevier, 2022-08-08) Maulu, Sahya; Langi, Sandra; Hasimuna, Oliver J.; Missinhoun, Dagoudo; Munganga, Brian P.; Hampuwo, Buumba M.; Gabriel, Ndakalimwe Naftal; Elsabagh, Mabrouk; Van Doan, Hien; Abdul Kari, Zulhisyam; Dawood, Mahmoud A.O.
The aquafeed industry continues to expand in response to the rapidly growing aquaculture sector. However, the identification of alternative protein sources in aquatic animal diets to replace conventional sources due to cost and sustainability issues remains a major challenge. Recently, insects have shown tremendous results as potential replacers of fishmeal in aquafeed. The present study aimed to review the utilization of insects in aquafeeds and their effects on aquatic animals' growth and feed utilization, immune response and disease resistance, and fish flesh quality and safety. While many insect species have been investigated in aquaculture, the black soldier fly (Hermetia illucens), and the mealworm (Tenebrio molitor) are the most studied and most promising insects to replace fishmeal in aquafeed. Generally, insect rearing conditions and biomass processing methods may affect the product’s nutritional composition, digestibility, shelf life and required insect inclusion level by aquatic animals. Also, insect-recommended inclusion levels for aquatic animals vary depending on the insect species used, biomass processing method, and test organism. Overall, while an appropriate inclusion level of insects in aquafeed provides several nutritional and health benefits to aquatic animals, more studies are needed to establish optimum requirements levels for different aquaculture species at different stages of development and under different culture systems.
Grain hermetic storage adoption in Northern Uganda: awareness, use, and the constraints to technology adoption
(Scientific Research Publishing, 2022-09-15) Okori, Francis; Cherotich, Sam; Abaca, Alex; Baidhe, Emmanuel; Adibaku, Francis; Onyinge, James Denis
Post-harvest storage losses (PHLs) remain significant in Sub-Saharan Africa (SSA) due to several factors mainly insect pests and molds. Hermetic storage technologies (HSTs) are being promoted to address these storage losses. In Uganda, HSTs were first introduced in 2012. However, its use among farming households remains low today. Data were collected from 306 smallholder farmers from four districts of Northern Uganda using a pre-tested semi-structured questionnaire to understand their knowledge, use, and constraints to the adoption of hermetic storage. A multivariate Logit regression model was used to find the significance of the factors affecting adoption. Results showed low awareness and use of hermetic storage among smallholder farmers. Only 53.3% of the interviewed farmers were aware of the use of hermetic storage for grain storage. The SuperGrain bag was the most known form of hermetic storage (35.3%), followed by the Purdue Improved Crop Storage (PICS) bag (34.9%), metallic silo (15.5%), and plastic silo (14.4%). Hermetic storage use was even lower as only 17.6% of the surveyed farmers were using one or more forms of hermetic storage to store their grains. Insect pest management without chemical insecticides was the main reason (83.1%) for hermetic storage use. About 75.5% of those aware of hermetic storage had received training in the technology. Hermetic storage use in farming households led to improved food availability, household income, and nutrition. Lack of local availability (50.2%), high costs (37.8%), and inadequate knowledge (6.9%) were the main constraints hindering the adoption of hermetic storage in Northern Uganda. The logit regression models showed that only training in hermetic storage significantly (p = 0.002) affected farmers’ decision to adopt hermetic storage. Understanding the factors that constrain the adoption of HSTs could provide policymakers with important information to initiate and design policies and programs aimed at reducing crop storage losses.
Compositional shifts in Microbial diversity under traditional banana cropping systems of Sub-Saharan Africa
(MDPI, 2022-05-16) Kaushal, Manoj; Tumuhairwe, John Baptist; Kaingo, Jacob; Malingumu, Richard; Nakamanya, Florence; Taulya, Godfrey; Coyne, Danny
Improvements in the crop productivity, soil health, and sustainable intensification should be premised on the better understanding of interactions between the cropping systems and soil microbial diversity. In this study, we assessed variations in the microbial communities across the traditional banana-based cropping systems of contrasting monocrop vigor (vigorous or V vs. nonvigorous or NV) and the cropping system (monocrop or MC vs. intercropped or IC) using 16S rDNA (V3–V4) and ITS2 amplicon deep sequencing via Illumina platform. Sequencing results of the bacterial and fungal communities showed high variability among MC and V cropping systems. The abundances of Proteobacteria, Firmicutes, and Actinobacteria were significantly higher in NV (non-vigorous) and V (vigorous) cropping systems; and the abundances of Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes in the MC (monocropping) than IC (intercropping). There were high relative abundances of Pseudomonas (6.1–37.43%), Bacillus (4.5–20.4%), Rhizobium (1.4–6.5%), and Devosia (1.5–6.7%) in the cropping systems. The dominant family of fungal class Incertae_sedis was Mortierellales, which accounted for 8.79–41.12% of total taxa. This result indicated that the cropping systems are vital for supporting the dynamic microbial diversity specifically beneficial for bacterial communities that helps in promoting synergistic plant-soil interactions and total productivity under resource poor conditions of smallholder farmers in sub-Saharan Africa (SSA).
Women and youths participation in agroforestry: What counts and what doesn’t around Mount Elgon, Uganda?
(Journal of Mountain Science, 2021-12-15) Galabuzi, Charles; Agaba, Hillary; Okia, Clement Akias; Odoul, Judith; Muthuri, Catherine
The increase in global climate change incidents is a glaring indication that more pragmatic and direct approaches to tree and forest management are urgently needed. A study was conducted around Mount Elgon Uganda between June 2018 and December 2019. The objectives were to: i) determine the socio-economic characteristics of women and youth farmers engaged in agroforestry, ii) determine the relationship between women and youth farmers’ characteristics in adoption of tree technologies and related decisions, and iii) assess the incentives, challenges and strategies for promoting agroforestry technologies’ adoption in the region. Data were collected from 250 women and youths using focus group discussions, semi-structured, and key informant interviews. Results showed that engagements in agroforestry practices attracted largely (82%) of uneducated women and youths and basic methods and tools were used to farm. Up to 70% of women and youth relied on crop farming as a major source of income, earning about USD$ 250 perannum. Farm and family size were positively (P>0.0001) related to tree adoption decisions while farmer capacity building activities (such as training, farmer guided field tours, and participatory farmer trial’s establishments) and access to low-cost tree seedlings motivated their involvement in tree planting. Land scarcity, soil, water, and tree conservation issues and shortage of desired tree species affected the extent of tree growing in both women and youth-led households. The suggested strategies comprised strengthening farmer capacity-building programs and upholding soil and water conservation technologies. Agroforestry has the potential to address the challenges related to land scarcity and shortage of desired tree products in women and youth-led households around Mount Elgon. However, the women and youths involved in farming activities were generally poor, illiterate and faced issues of land insecurity. These factors, limited their full potential and interest in agroforestry. A significant increase in tree adoption rates by women and youths will be achieved with increased training on tree seed collection and pre-treatment, reforestation programs as well as tree pest and disease control.
Women and youths participation in agroforestry: what counts and what doesn’t around Mount Elgon, Uganda?
(Science Press, 2021-09-13) Galabuzi, Charles; Agaba, Hillary; Okia, Clement Akias; Odoul, Judith; Muthuri, Catherine
The increase in global climate change incidents is a glaring indication that more pragmatic and direct approaches to tree and forest management are urgently needed. A study was conducted around Mount Elgon Uganda between June 2018 and December 2019. The objectives were to: i) determine the socio-economic characteristics of women and youth farmers engaged in agroforestry, ii) determine the relationship between women and youth farmers’ characteristics in adoption of tree technologies and related decisions, and iii) assess the incentives, challenges and strategies for promoting agroforestry technologies’ adoption in the region. Data were collected from 250 women and youths using focus group discussions, semi-structured, and key informant interviews. Results showed that engagements in agroforestry practices attracted largely (82%) of uneducated women and youths and basic methods and tools were used to farm. Up to 70% of women and youth relied on crop farming as a major source of income, earning about USD$ 250 perannum. Farm and family size were positively (P>0.0001) related to tree adoption decisions while farmer capacity building activities (such as training, farmer guided field tours, and participatory farmer trial’s establishments) and access to low-cost tree seedlings motivated their involvement in tree planting. Land scarcity, soil, water, and tree conservation issues and shortage of desired tree species affected the extent of tree growing in both women and youth-led households. The suggested strategies comprised strengthening farmer capacity-building programs and upholding soil and water conservation technologies. Agroforestry has the potential to address the challenges related to land scarcity and shortage of desired tree products in women and youth-led households around Mount Elgon. However, the women and youths involved in farming activities were generally poor, illiterate and faced issues of land insecurity. These factors, limited their full potential and interest in agroforestry. A significant increase in tree adoption rates by women and youths will be achieved with increased training on tree seed collection and pre-treatment, reforestation programs as well as tree pest and disease control.
Batch fermentation of succinic acid from cheese whey by Actinobacillus succinogenes under variant medium composition
(Springer, 2021-07-29) Omwene, Philip Isaac; Yağcıoğlu, Meltem; Öcal-Sarihan, Zehra Betül; Ertan, Fatma; Keris-Sen, Ülker Diler; Karagunduz, Ahmet; Keskinler, Bülent
Bio-based succinic acid production has attracted global attention since its consideration as a potential replacement to petroleum-based platform chemicals. This study used three different CO2 sources, namely NaHCO3, K2CO3 and MgCO3 for fermentation of succinic acid (SA) by Actinobacillus succinogenes under three distinct substrate conditions i.e. lactose, whey and whey devoid of any supplements. Batch experiments were performed in both anaerobic flasks and 5L benchtop fermenter. SA fermentation in anaerobic flasks was unfettered by supplementary nutrients. However, fermentation in the benchtop fermenter devoid of supplementary nutrients resulted into 42% reduction in SA yield as well as lower SA productivities. Furthermore, a significant reduction of cell growth occurred in anerobic flasks at pH < 6.0, and complete termination of bacterial activity was noted at pH < 5.3. The highest SA titer, yield and productivity of 15.67 g/L, 0.54 g/g and 0.33 g/L/h, respectively, was recorded from whey fermentation with MgCO3. The present study further highlights significant inhibitory effect of K2CO3 buffered medium on Actinobacillus succinogenes. Thus, we can claim that environmental pollution as well as costs of SA production from whey can be reduced by leveraging on whey residual nutrients to support the activity of Actinobacillus succinogenes.
Bio-based succinic acid recovery by ion exchange resins integrated with nanofiltration/reverse osmosis preceded crystallization
(Elsevier, 2021-07-03) Omwenea, Philip Isaac; Sarihan, Zehra Betul Ocal; Karagunduz, Ahmet; Keskinlera, Bulen
Succinic acid is a key platform chemical for production of various products such as biodegradable polymers, pharmaceuticals, fine chemicals and foods. In the present study, bio-based succinic acid was recovered through two processes. Process I consisted of chromatographic separation with anionic exchange resin followed by direct crystallization, whereas process II sequentially consisted of cationic exchanger, activated carbon, NF/RO membrane, vacuum distillation, and crystallization. The highest chromatographic separation efficiency for succinic acid by Amberlite IRA900 Cl column was calculated as 69.3% at flow rate of 0.42 BV/h. Rejection of succinic aid (SA), lactic acid (LA), formic acid (FA) and acetic acid (AC) by NF90 membrane was 53.1, 51.8, 46.6 and 39.8%, respectively at pH less than 2. However, at pH 6.8 the respective rejections increased to 96.8, 90.6, 71.3 and 70.5%. Double pass with BW30 or HP reverse osmosis membranes achieved retention of SA, LA, FA and AC of 95.9%, 95.8%, 65.4% and 46.9%, respectively. Analysis of generated SA crystals by X-ray diffraction technique (XRD) and Fourier transform infrared (FTIR) showed the crystallinity of recovered SA as conformable to standard grade crytsals. The purity of generated succinic acid crystals was recorded as 98.5% and 96.7% for process I and process II, respectively. The calculated succinic acid yield was 78% for process I and 65% for process II. Herein, we demonstrated two alternative systems for bio-based succinic acid recovery, which will set a stage for research in efficient downstream purification of SA.
Phosphorous removal from anaerobically digested municipal sludge centrate by an electrocoagulation reactor using metal (Al, Fe and Al-Fe) scrap anodes.
(Elsevier, 2021-06-02) Kobya, Mehmet; Omwenea, Philip Isaac; Sarabia, Sanaz Mohammadzadeh; Yildirim, Sadullah; Ukundimana, Zubeda
Phosphates are a major cause of eutrophication and growth of algal blooms in surface waters. The current study investigated phosphorus removal from sludge centrate effluent (SCE) of a municipal wastewater plant by packed-bed electrocoagulation (EC) reactor. Distinctively, iron (Fe), aluminum (Al) and Al-Fe hybrid scrap anodes were used. The influence of initial pHi, applied current and packed anode bed density were evaluated. Phosphorous removal efficiency of 99.99 % was obtained at applied current of 0.20A with anode bed densities of 0.18 kg Al/m3 (pHi 5.0) and 0.48 kg Fe/m3(pHi 7.0). Optimum operating costs entailing sludge disposal, chemical, energy and electrode consumption were calculated as 0.379 US $/m3 (6.04 $/kg PO4-P) for Fe scrap, 0.494 US $/m3 (9.46 $/kg PO4-P) for Al scrap and 0.501 US $/m3 (9.59 $/kg PO4-P) for Al-Fe hybrid scraps. Phosphorus removal per electrochemically generated metal was 191.22 mg P/g Al, 104.88 mg P/g Fe, and 61.08 mg P/g (Al + Fe). The molar metal to phosphorus ratio at optimum conditions were calculated as 5.41, 3.97 and 7.65 mol/mole for Al, Fe and Al-Fe, respectively. The key mechanisms for phosphorus removal were metal-phosphorus precipitation and adsorption. Herein, metal scrap anodes have been proved effective for phosphorous removal from SCE.

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