Direct bioethanol production by amylolytic yeast Candida albicans

作者：Aruna A^*; Nagavalli M; Girijashankar V; Ponamgi S P D; Swathisree V; Rao L Venkateswar

来源：Letters in Applied Microbiology, 2015, 60(3): 229-236.

DOI：10.1111/lam.12348

• bioethanol production
• Candida albicans
• glucoamylase
• mutagenesis
• optimization of fermentation

An attempt was made to produce bioethanol using optimized fermentation parameters and mutationally improved strain of Candida albicans. The mutant strain OMC3E6 obtained by UV irradiation followed by ethidium bromide successive mutations showed 26 times more glucoamylase secretion and 15 times more bioethanol production via direct conversion of starch. Enhanced hydrolysis of insoluble starch (72%) and potato starch (70%) was achieved with glucoamylase enzyme preparation from mutant C.albicans. In fermentation medium, the use of maltose, corn steep liquor, NaH2PO4, NaCl+MgSO4 and Triton X-100 has increased the glucoamylase production by the microbe. Under optimized conditions, C.albicans eventually produced 437gethanolkg(-1) potatoes. Earlier reports mentioned the use of thrice the quantity of starch as reported by us followed by more fermentation period (3-4days) and demanded pretreatment of starch sources with alpha-amylase as well. Here, we simplified these three steps and obtained 73% conversion of insoluble starch into ethanol via direct conversion method in a period of 2days without the involvement of cell immobilizations or enzyme pretreatment steps.

• 出版日期2015-3