产胞外多糖海洋乳酸菌的筛选及其多糖发酵工艺优化  

Screening of Marine Lactic Acid Bacteria Producing Exopolysaccharide and Optimization of Polysaccharide Fermentation Technology

作　　者：安敏 刘唤明[1] 钟秋红 周春霞[1] 洪鹏志[1] 钟赛意[1] 邓楚津[1] AN Min;LIU Huanming;ZHONG Qiuhong;ZHOU Chunxia;HONG Pengzhi;ZHONG Saiyi;DENG Chujin(College of Food Science and Engineering,Guangdong Ocean University/Guangdong Aquatic Products Processing and Key Laboratory,Zhanjiang 524088,China)

机构地区：[1]广东海洋大学食品科技与工程学院/广东省水产品加工与重点实验室,广东湛江524088

出　　处：《广东海洋大学学报》2023年第5期106-112,共7页Journal of Guangdong Ocean University

基　　金：湛江市科技计划(2020A02006);南方海洋科学与工程重点实验室(湛江)资助项目(ZJW-2019-07);广东省重点领域研发计划(2020B1111030004);国家重点研发计划重点专项(2019YFD0902005);广东省高校科技创新团队项目(2021KCXTD021)。

摘　　要：【目的】筛选产胞外多糖(exopolysaccharide,EPS)的海洋乳酸菌,优化产EPS的发酵工艺,为海洋源乳酸菌胞外多糖的开发利用提供参考。【方法】通过菌落观察、革兰染色、接触酶检验,从湛江沿海的海水、海泥、红树林土壤及鱼肠中初步分离乳酸菌;利用菌落拉丝法结合多糖产量筛选出产EPS的乳酸菌;对EPS产量最高的菌株进行16S rDNA鉴定;以DPPH自由基清除率和总还原力为判据初步评估EPS的抗氧化能力;采用单因素及正交实验得到该菌株产EPS的最佳条件。【结果与结论】共筛出4株产EPS的乳酸菌,分别命名为LAN4、LAH5、LAF1和LAY1。其中以菌株LAN4的EPS产量最高,为(94.63±5.86)mg/L。经16S rDNA鉴定,LAN4为发酵黏液乳杆菌(Limosilactobacillus fermentum)。5 mg/mL的LAN4 EPS可清除50.02%的DPPH自由基,总还原力相当于224.74μg/mL的维生素C。菌株LAN4产EPS的最佳培养条件为:葡萄糖添加量30 g/L,酵母蛋白胨添加量40 g/L,发酵时间16 h,发酵温度41℃,在此条件下培养LAN4菌株EPS的产量为(307.53±26.78)mg/L。【Objective】In order to screen marine lactic acid bacteria that produce exopolysaccharide(EPS),and optimize the technology of producing EPS,and provide a reference for the development and utilization of EPS from marine lactic acid bacteria.【Methods】Lactic acid bacteria were initially isolated from material through colony observation,Gram staining,and catalase test methods,then lactic acid bacteria producing EPS were further screened by colony wire drawing and EPS yield.Moreover,the strain with the highest EPS yield was identified by 16S rDNA method.Furthermore,the antioxidant capacity of EPS was preliminarily evaluated by DPPH radical scavenging rate and total reducing capacity,and the optimum conditions of EPS production were obtained by a single-factor experiment and orthogonal test. 【Results and Conclusion】 Four strains of lactic acid bacteria producing EPS were successfully screened and named LAN4, LAH5, LAF1, and LAY1, respectively. Among these four strains, LAN4 showed the highest EPS yield and was identified as Limosilactobacillus fermentum by 16S rDNA method. The concentration of EPS at 5 mg/mL could scavenge 50.02% of DPPH free radicals and the total reducing power was equivalent to 224.74 μg/mL vitamin C. Besides, the optimal culture conditions for EPS production by strain LAN4 were: 30 g/L glucose addition, 40 g/L yeast peptone addition, 16 h fermentation time, and 41 ℃ fermentation temperature. Under these conditions, the EPS yield of LAN4 was (307.53 ± 26.78) mg/L.

关 键 词：海洋乳酸菌 发酵黏液乳杆菌 胞外多糖 抗氧化 发酵工艺 

分 类 号：Q939.9[生物学—微生物学] TQ920.6[轻工技术与工程—发酵工程]