Browsing by Author "Nanyonga, Sarah"

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    Feasibility of a novel on-site detection method for aflatoxin in maize flour from markets and selected households in Kampala, Uganda
    (MDPI AG, 2018-08-11) Wacoo, Alex Paul; Wendiro, Deborah; Nanyonga, Sarah; Hawumba, Joseph F.; Sybesma, Wilbert; Kort, Remco
    In sub-Saharan Africa, there is a high demand for affordable and accessible methods for on-site detection of aflatoxins for appropriate food safety management. In this study, we validated an electrochemical immunosensor device by the on-site detection of 60 maize flour samples from six markets and 72 samples from households in Kampala. The immunosensor was successfully validated with a linear range from 0.7 ± 0.1 to 11 ± 0.3 µg/kg and limit of detection (LOD) of 0.7 µg/kg. The maize flour samples from the markets had a mean total aflatoxin concentration of 7.6 ± 2.3 µg/kg with approximately 20% of the samples higher than 10 µg/kg, which is the maximum acceptable level in East Africa. Further down the distribution chain, at the household level, approximately 45% of the total number contained total aflatoxin levels higher than the acceptable limit. The on-site detection method correlated well with the established laboratory-based HPLC and ELISA-detection methods for aflatoxin B1 with the correlation coefficients of 0.94 and 0.98, respectively. This study shows the feasibility of a novel on-site detection method and articulates the severity of aflatoxin contamination in Uganda.
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    Utilization of solid waste as a substrate for production of oil from oleaginous microorganisms
    (Hindawi, 2018-05-16) Laker, Fortunate; Agaba, Arnold; Akatukunda, Andrew; Gazet, Robert; Barasa, Joshua; Nanyonga, Sarah; Wendiro, Deborah; Wacoo, Alex Paul
    The overwhelming demand of oil and fats to meet the ever increasing needs for biofuel, cosmetics production, and other industrial purposes has enhanced a number of innovations in this industry. One such innovation is the use of microorganisms as alternative sources of oil and fats. Organic solid waste that is causing a big challenge of disposal worldwide is biodegradable and can be utilized as substrate for alternative oil production.The study evaluated the potential of isolated yeast-like colonies to grow and accumulate oil by using organic solid waste as substrate. Of the 25 yeast-like colonies isolated fromthe soil samples collected fromthree different suburbs in Kampala district, Uganda, 20 were screened positive for accumulation of lipid but only 2 were oleaginous. The NHC isolate with the best oil accumulation potential of 48.8% was used in the central composite design (CCD) experiments. The CCD experimental results revealed a maximum oil yield of 61.5% from 1.25 g/L cell biomass at 10 g/L of solid waste and temperature of 25∘C. The study revealed that organic solid waste could be used as a substrate for microbial oil production.