Browsing by Author "Hamadi, Said"

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    Isolation and Identification of Local Ethanolic Yeasts Inhabiting Coffee Processing Environments in Tanzania
    (2014-12-20) Hamadi, Said; Muruke, Masoud H.; Hosea, Ken M.M.
    Coffee processing environment harbours different microbiota of fungi and bacteria, some of which are of great economic value. This study isolated, screened and identified indigenous yeast associated with ethanol production potential in coffee processing environments of Mbinga in Ruvuma region and Hai in Kilimanjaro region using standard procedures. Yeast identification was done by amplification and sequencing D1/D2 domain of the gene 26S rDNA. A total of 21 yeast isolates were obtained from both sites and only 8 of them were able to ferment glucose. All 9 isolates fermented coffee pulp waste to ethanol at varying levels. Highest ethanol production was observed by isolate M4, which produced 3% (v/v) ethanol, followed by PDA4MB (2.8% v/v), PDA3 (2.6% v/v) and the least was by M2 which produced only 1.1% (v/v).Three isolates showed good attribute to ethanol production (2.76 to 3.56% v/v) even after an addition of higher sugar concentrations to coffee pulp waste. The basic local alignment search tool (BLAST) and phylogenetic analysis revealed the identity of the yeasts as Pichia kudriavzevii, Issatchenkia orientalis, Clavispora lusitaniae, Pichia guilliermondii, and Pichia anomala, all of them known to be associated with ethanol fermentation. Their attributes towards ethanol fermentation are taken to be potential for further investigation for bioethanol production.
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    Optimization of Fermentation Parameters for Production of Ethanol from Coffee Pulp Waste Using Pichia anomala M4 Yeast Isolated from Coffee Environment in Tanzania
    (2014-11-10) Hamadi, Said; Muruke, Masoud H.; Hosea, Ken M.M.
    Abstract Coffee pulp waste (CPW), an abundant agro-waste available in Tanzania was studied as a potential substrate for bioethanol production. Selected yeast Pichia anomala M4 previously isolated from coffee environment was tested against three fermentation parameters namely pH, temperature and soy flour supplementation. Maximum ethanol of 4.7% (v/v) and 4.07% was produced at an optimum pH 4.5 and temperature of 30 0C respectively. There was a significant increase (ANOVA, P˂0.05) in ethanol production on addition of soy flour as a supplement with a maximum yield of 6.04% (v/v) ethanol at a soy flour concentration of 2.0% g/l. A slight increase on ethanol production (6.3% v/v) was recorded when all the three parameters were put together. Appreciable amount of sugar content (8.2 g/l) found in CWP and significant levels of ethanol produced by yeast from the agricultural waste, calls for more research on how best to utilize this untapped bioresource.