초록
<P>Several biotechnological applications have been investigated using <I>Kluyveromyces</I> spp. yeast, considering their high metabolic diversity. This study suggests the usage of two newly isolated halotolerant <I>K. marxianus</I> strains obtained from cheese and pickle wastes could be used for bioethanol production in molasses medium. Some important parameters such as pH (4, 5, 6, 7), fermentation period (4, 8, 12, 24 h), initial substrate loading (6, 8, 10, 12, 14 v/v %), and salt concentrations (2, 4, 6, 8, 10 w/v %) were optimized in the first experiments of the study, which showed that the optimum medium was the one containing 10 v/v % molasses solution and 4 w/v % NaCl. The highest ethanol yield was obtained after 12 h of fermentation at pH 5 in the first isolate and at pH 6 in the second one. Moreover 7.90 and 7.92 g/L of ethanol, corresponding to 0.65 g/L.h of productivity and 39.2% and 39.1% theoretical ethanol yield achieved respectively. It is also worth to mention here that considerable ethanol quantities such as 2.84 and 2.65 g/L were obtained even at 10% salt concentration. To the best of our knowledge this is the first report on usage of halotolerant <I>K. marxianus</I> in molasses‐based ethanol production. © 2018 American Institute of Chemical Engineers Environ Prog, 38: 542–547, 2019</P>