Screening, identification and culture medium optimization of a hypoglycemic Lysinibacillus fusiformis strain from common carp
YU Junfei, XIA Banghua*, HAO Qirui, ZOU Haobo, WANG Peng, CHEN Zhongxiang,GAO Lei, WU Song, HUANG Li, QIN Dongli*, HAN Ying*
1.Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China; 2.College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China; 3.China Animal Husbandry Industry Company Limited, Beijing 100070, China; 4.Key Laboratory of Control of Quality and Safety for Aquatic Products, Ministry of Agriculture and Rural Affairs, Beijing 100141, China
Abstract: In order to investigate the hypoglycemic function of bacillus Lysinibacillusfusiformis and thus enhance its metabolite concentration, bacteria with proteolytic ability were screened from common carp Cyprinuscarpio intestinal contents by protease production ability assay, and their ability to produce dipeptidyl peptidase-Ⅳ (DDP-Ⅳ) inhibitor was measured. The screened strains were isolated, purified and cultured, then identified by 16S rRNA sequencing and physiological and biochemical characteristics, and the medium formulation of the strains was by single-factor test and response surface optimization experiment. The results showed that the CR-3 strain, with the ability to produce 62.35% at 37 ℃, was identified as L.fusiformis by physiological and biochemical identification and phylogenetic tree construction. The optimum fermentation medium was consisted of 1.46% sucrose, 0.55% CaCO3, 0.48% NH4Cl and 2.10% soybean meal, with 64% higher DDP-Ⅳ inhibitor yield than the strain unoptimized. The findings indicate that the L.fusiformis screened in this experiment has good ability to produce DDP-IV inhibitor and has potential hypoglycemic function.
2022, Vol. 37 
