Ethanogenic fermentation of co-cultures of Candida shehatae HM 52.2 and Saccharomyces cerevisiae ICV D254 in synthetic medium and rice hull hydrolysate

• Published in: Bioresource technology 2013-03, Vol.131, p.508-514
• Main Authors: Hickert, Lilian Raquel, da Cunha-Pereira, Fernanda, de Souza-Cruz, Priscila Brasil, Rosa, Carlos Augusto, Ayub, Marco Antônio Záchia
• Format: Article
• Language: English
• Subjects: Bioethanol; Biofuel production; Biological and medical sciences; Bioreactors; Biotechnology; Candida - classification; Candida - metabolism; Candida shehatae; Cell Fractionation; Coculture Techniques - methods; Energy; Ethanol; Ethanol - isolation & purification; Ethanol - metabolism; ethanol production; Ethyl alcohol; Feasibility Studies; Fermentation; Food industries; Fundamental and applied biological sciences. Psychology; glucose; Glucose - metabolism; Hydrolysates; Hydrolysis; Industrial applications and implications. Economical aspects; Methods. Procedures. Technologies; Microbial engineering. Fermentation and microbial culture technology; Oryza - microbiology; oxygen; Rice; Rice hull hydrolysate; rice hulls; Saccharomyces cerevisiae; Saccharomyces cerevisiae - classification; Saccharomyces cerevisiae - metabolism; Seeds - microbiology; Species Specificity; Sugars; Use and upgrading of agricultural and food by-products. Biotechnology; xylose; Xylose - metabolism; yeasts
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2012.12.135

► Candida shehatae HM 52.2 is newly isolated; it was never used in bioprocess before. ► Rice hull was hydrolysed in order to be used as substrate for bioethanol production. ► Co-cultures of C. shehatae and S. cerevisiae were used to ferment rice hull hydrolysate RHH. ► Experiments were run in shaker and further scaled-up to bioreactor. ► The results showed near-theoretical yields of ethanol in the co-culture. The ability of Candida shehatae, Saccharomyces cerevisiae, or the combination of these two yeasts in converting the mixed sugar composition of rice hull hydrolysate (RHH) as substrate for ethanol production is presented. In shake flask experiments, co-cultures showed ethanol yields (YP/S) of 0.42 and 0.51 in synthetic medium simulating the sugar composition of RHH and in RHH, respectively, with both glucose and xylose being completely depleted, while pure cultures of C. shehatae produced slightly lower ethanol yields (0.40). Experiments were scaled-up to bioreactors, in which anaerobiosis and oxygen limitation conditions were tested. Bioreactor co-cultures produced similar ethanol yields in both conditions (0.50–0.51) in synthetic medium, while in RHH, yields of 0.48 and 0.44 were obtained, respectively. The results showed near-theoretical yields of ethanol. Results suggest the feasibility of co-cultures of C. shehatae, a newly isolated strain, and S. cerevisiae in RHH as substrate for second-generation ethanol production.