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. | Turkish Journal of Biology Turk J Biol (2013) 37: 259-264 © TÜBİTAK doi: Research Article Biopolymer generation from sweet sorghum juice: screening, isolation, identification, and fermentative polyhydroxyalkanoate production by Bacillus aryabhattai 1 2 3 4, Varavut TANAMOOL , Tsuyoshi IMAI , Paiboon DANVIRUTAI , Pakawadee KAEWKANNETRA * 1 Graduate School of Khon Kaen University, Khon Kaen 40002, Thailand 2 Division of Environmental Science and Engineering, Yamaguchi University, Tokiwadai, Ube, Yamaguchi 755-8611, Japan 3 Fermentation Research Center for Value Added Agricultural Products, Faculty of Technology, Khon Kaen University, Khon Kaen 40002, Thailand 4 Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002, Thailand Received: Accepted: Published Online: Printed: 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 g/L with dry cell weight and yield maximum hourly productivity at 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 ( similarity). Interestingly, there has been as of yet no report on the use of this strain to produce an added-value biopolymer of PHA. Key words: Biopolymer, polyhydroxyalkanoates, sweet sorghum juice, fermentation, Bacillus aryabhattai 1. Introduction Synthetic plastics, .