Bioethanol fermentation from kitchen waste using Saccharomyces cerevisiae

Bioethanol obtained from microbial fermentation can replace conventional fossil fuels to satisfy energy demand. In this respect, a fermenting isolate of Saccharomyces cerevisiae, obtained from date juice, was grown in YEPD medium as a part of a previous published research project. In this study, the isolate was tentatively characterized for alcoholic fermentation in organic kitchen waste medium, prepared from discarded fruit and vegetable peels. Fermentation in shaking condition resulted in the production of 7.3% (v/v) ethanol after 48 h, after which the pH of the medium increased slightly in response. Further research should be conducted to assess the potential of kitchen waste as a raw material in ethanol fermentation.

Effect of Various Parameters on the Growth and Ethanol Production by Yeasts Isolated from Natural Sources

Two ethanol fermenting Saccharomyces cerevisiae were isolated from date juice and grapes and grown in YEPD medium. They were characterized for alcoholic fermentation using sugarcane molasses and their growth conditions were optimized with respect to pH and sugar concentration. Results revealed a temperature of 30ºC, pH 6.0 and 6.5% sugar concentration as optimum for fermentation. Stress tolerance tests showed that date juice isolate was highly tolerant to temperature, pH and high ethanol concentration in the medium. Under optimized conditions, S. cerevisiae isolated from date-juice produced 7.75% of ethanol in molasses as estimated by Conway method.Bangladesh J Microbiol, Volume 30, Number 1-2,June-Dec 2013, pp 49-54

The expression of the Candida albicans gene SAP4 during hyphal formation in human serum and in adhesion to monolayer cell culture of colorectal carcinoma Caco-2 (ATCC)

Candida albicans SAP4 gene encodes secretory aspartyl protease Sap4 which is involved in hyphae formation and virulence. Transcriptional factors Cph1 and Efg1 govern the expression of several C. albicans genes and contribute to morphogenesis. We investigated the expression of SAP4 in C. albicans clinical isolate and mutants lacking Efg1 or/ and Cph1 grown in human serum and during contact with Caco-2 cell line. mRNA was analyzed with the use of RT-PCR; relative quantification was normalized against an ACT1 in cells after 18-h growth either in serum or on monolayer as well as in their counterparts in YEPD medium. We assessed the role of Sap4, Efg1 and Cph1 in adhesion of C. albicans to epithelial cells. Additionally, adherence assay was performed with sap4/sap4. Adhesion was expressed as a percent of adherent cells to monolayer at 90 min vs. total cells added (100%). No differences were observed in adhesion of efg1/efg1 and sap4/sap4 compared with SC5314 (P≥0.05 statisitically insignificant). SAP4 expression indicated that it is not involved in adapting to the tested conditions. SAP4 expression can be strainspecific and is not solely controlled by the Efg1 pathway but also by the Cph1 pathway. Neither Efg1 nor Sap4 can influence adhesion.