Biopolymer generation from sweet sorghum juice: Screening, isolation, identification, and fermentative polyhydroxyalkanoate production by Bacillus aryabhattai

Abstract

This study aims to use sweet sorghum juice (SSJ) to produce an environmentally friendly biopolymer of polyhydroxyalkanoates (PHAs) by bacteria isolated from soil. Among 18 isolates, only 3 isolates, coded as S4, S6, and S11, were chosen to produce PHA via batch fermentation compared to 3 strains of Alcaligenes eutrophus, A. latus, and Hydrogenophaga sp., respectively, under controlled conditions at pH 7, 35 °C, and 20 g/L of initial total sugar in the SSJ. The results clearly showed that the isolate S4 can produce maximum PHAs of 1.74 g/L with 57.62% dry cell weight and yield maximum hourly productivity at 0.097 g/L. S4 was further identified by full-length 16S rDNA gene sequence homology, and the findings showed that it was closely related to Bacillus aryabhattai (99.70% similarity). Interestingly, there has been as of yet no report on the use of this strain to produce an added-value biopolymer of PHA. © TÜBİTAK.