Abstract：
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.
摘要：
一株高产微生物多糖菌株,命名为RM1603，是从根际土壤中分离出来的，并通过形态和系统发育分析进行了鉴定。通过薄层色谱和红外光谱鉴定胞外多糖（EPS）。在摇瓶和5-L发酵罐中通过单因素实验优化了发酵条件。形态学和系统发育树分析结果表明，RM1603是一株普鲁兰幼树。其微生物多糖被鉴定为普鲁兰，摇瓶中EPS的生产能力达到33.07±1.03gL-1。在5-L发酵罐中优化了发酵条件，并发现包含6.5的初始pH，2vvm的曝气速率，转子转速为600rpm，接种量为2%。在这些条件下,RM1603的支链淀粉产量达到62.52±0.24gL-1。因此，本研究有助于RM1603作为一种新的高产普鲁兰分离菌，在生物技术中具有潜在的应用价值。
