Characteristic analysis and fermentation optimization of a novel Aureobasidium pullulans RM1603 with high pullulan yield

• Published in: Journal of bioscience and bioengineering 2024-05, Vol.137 (5), p.335-343
• Main Authors: Chen, Jiale, Lu, Ye, Liu, Li, Bai, Ruoxuan, Zhang, Shuting, Hao, Yaqiao, Xu, Fangxu, Wei, Buyun, Zhao, Hongxin
• Format: Article
• Language: English
• Subjects: Aureobasidium pullulans; Microbial polysaccharides; Phylogenetic analysis; Pullulan
• ISSN: 1389-1723; 1347-4421
• DOI: 10.1016/j.jbiosc.2023.12.018

A high-yielding microbial polysaccharide-producing strain, named RM1603, was isolated from rhizosphere soil and identified by morphological and phylogenetic analysis. The extracellular polysaccharides (EPS) were identified by thin-layer chromatography and infrared spectroscopy. The fermentation conditions were optimized by single factor experiments in shake flasks and a 5-L fermentor. The results of morphological and phylogenetic tree analysis showed that RM1603 was a strain of Aureobasidium pullulans. Its microbial polysaccharide was identified as pullulan, and the EPS production capacity reached 33.07 ± 1.03 g L−1 in shake flasks. The fermentation conditions were optimized in a 5-L fermentor, and were found to encompass an initial pH of 6.5, aeration rate of 2 vvm, rotor speed of 600 rpm, and inoculum size of 2 %. Under these conditions, the pullulan yield of RM1603 reached 62.52 ± 0.24 g L−1. Thus, this study contributes RM1603 as a new isolation with high-yielding pullulan and potential application value in biotechnology.