Xu Xiaopeng, Nie Zuoming, Zheng Zhiyong, Zhu Li, Zhan Xiaobei
The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.
J Mol Microbiol Biotechnol. 2017;27(1):55-63. doi: 10.1159/000452835. Epub 2017 Jan 17.
This study aimed to investigate the effect of nitrogen sources on the production and rheological properties of welan gum produced by Sphingomonas sp. ATCC 31555. Six different nitrogen sources were used for ATCC 31555 fermentation, and 2 of these were further analyzed due to their more positive influence on welan gum production and bacterial biomass. Bacterial biomass, welan gum yield, welan viscosity, molecular weight, monosaccharide composition, acyl content, and welan structure were analyzed. Welan gum production and the biomass concentration of ATCC 31555 were higher in media containing NaNO3 and beef extract. Welan viscosity decreased at higher temperatures of 30-90°C, and it increased with a higher welan concentration. In the media containing NaNO3 (3 g·L-1), welan viscosity was higher at 30-70°C and a welan solution concentration of 6-10 g·L-1. With a reduced NaNO3 concentration, the molecular weight of welan gum and the molar ratio of mannose decreased, but the molar ratio of glucuronic acid increased. With different nitrogen sources, the acetyl content of welan gum differed but its structure was similar. NaNO3 and beef extract facilitated welan production. A reduced NaNO3 concentration promoted welan viscosity.
本研究旨在探究氮源对鞘氨醇单胞菌属（Sphingomonas sp.）ATCC 31555产生的韦兰胶的产量及流变学性质的影响。六种不同的氮源用于ATCC 31555的发酵，其中两种因其对韦兰胶产量和细菌生物量有更积极的影响而被进一步分析。分析了细菌生物量、韦兰胶产量、韦兰胶粘度、分子量、单糖组成、酰基含量和韦兰胶结构。在含有硝酸钠和牛肉膏的培养基中，ATCC 31555的韦兰胶产量和生物量浓度更高。韦兰胶粘度在30 - 90°C的较高温度下降低，且随着韦兰胶浓度的升高而增加。在含有3 g·L-1硝酸钠的培养基中，在30 - 70°C以及6 - 10 g·L-1的韦兰胶溶液浓度下，韦兰胶粘度更高。随着硝酸钠浓度降低，韦兰胶的分子量和甘露糖摩尔比降低，但葡萄糖醛酸摩尔比增加。使用不同的氮源时，韦兰胶的乙酰基含量不同但其结构相似。硝酸钠和牛肉膏促进韦兰胶的产生。硝酸钠浓度降低会提高韦兰胶粘度。
