1.College of Food Science and Engineering, The Key Laboratory of Aquatic Product Processing and Utilization of Liaoning Province, Dalian Ocean University，Dalian 116023, China; 2.National Research & Development Branch Center for Seaweed Processing(Dalian)，Dalian 116023, China
Abstract: In order to obtain low molecular fucoidan oligosaccharide, a strain of bacterium producing fucoidan(FUC)degrading enzyme was screened with fucoidan extracted from Kjellmanniellacrassifolia as the sole carbon source.Conditions of the strain growth and enzyme production were optimized via FUC concentration(0, 1, 2, 4, 8 and 12 g/L), yeast powder(1, 3, 6, 9, 12 and 14 g/L), NaCl(0, 20, 30, 40 and 50 g/L), pH(5, 6, 7, 8 and 9), culture temperature(20, 25, 30, 35 and 40 ℃)and inoculum(2%, 5%, 10% and 15%)and the enzymatic properties of crude enzyme were investigated.The fucoidan oligosaccharide degraded by the enzyme was isolated and purified by Sephacryl S-100, and its monosaccharide composition was analyzed.The identification results of 16S rRNA showed that the preferred strain belonged to Sinomicrobium sp..The optimum medium composition was FUC mass concentration of 2 g/L, yeast concentration of 12 g/L, NaCl concentration of 20 g/L and initial pH of 6.The highest enzyme activity by fermentation was obtained under conditions of 25 ℃, 100 mL of liquid and 1% of inoculation, the enzyme activity being increased by 50.8% to 143.60 U/mL, and the biomass OD600 nm value was 1.666 after optimization.The enzymatic properties showed that the optimum enzymatic hydrolysis was found to be temperature of 35 ℃, pH of 8 and the metal ion concentrations(Li +, K + and Ba2 +)of 10 and 5 mmol/L, promoting the enzyme production ability of Sinomicrobium sp.Fuc19, and the different concentrations of EDTA, Al3 + and Fe3 + inhibiting the enzyme activity.The analysis of monosaccharide composition of degraded oligosaccharides showed that they were primarily composed of fucose and galactose.The findings indicated that the strain producing fucoidan degrading enzyme from Sinomicrobium sp.Fuc19 was efficient and safe, and that had great application potential.
国晶晶, 刘诗萌, 韩梓琪, 宋悦凡, 刘舒, 周慧, 汪秋宽. 褐藻聚糖硫酸酯降解酶菌Sinomicrobium sp Fuc19的产酶优化及其降解产物化学组成[J]. 大连海洋大学学报, 2022, 37(2): 285-294.
GUO Jingjing, LIU Shimeng, HAN Ziqi, SONG Yuefan, LIU Shu, ZHOU Hui, WANG Qiukuan. Production optimization of fucoidan degrading enzyme stain Sinomicrobium sp.Fuc19 and the chemical composition of its hydrolyzed products. Journal of Dalian Ocean University, 2022, 37(2): 285-294.
2022, Vol. 37 
