富集钙乳酸菌的筛选及培养条件对富集效果的影响

Screening of Calcium-enriched Lactic Acid Bacteria and the Effect of Culture Conditions on Calcium-enriched

为筛选具有较强钙转化富集能力的乳酸菌(后续用于鱼骨泥发酵),本文研究了七种乳酸菌(植物乳杆菌CY1-1、植物乳杆菌Z7、戊糖片球菌DBY2-5-1、干酪乳杆菌D400、米酒乳杆菌DL10、嗜酸乳杆菌DL12、清酒乳杆菌YP4-5)及其复合菌株的生长能力、产酸能力和钙富集能力,研究了钙离子浓度、生长时间、pH、温度对初筛菌株钙富集能力的影响,并通过原子力显微镜观察菌体富集前后的表面结构差异,研究乳酸菌的形态变化及钙离子吸附机制。结果表明,单一菌株中钙富集量最高的是植物乳杆菌CY1-1,其次为植物乳杆菌Z7。钙富集能力较强的复合菌株为CY1-1+DL12、Z7+YP4-5,富集量分别较单一菌株提高了6.76和21.69 mg/g。试验菌株在稳定期时的钙富集能力优于对数期,最适富集的钙离子浓度为1.2 mg/mL,Z7菌株的最适pH为6,Z7+YP4-5、CY1-1、CY1-1+DL12菌株的最适pH为7.2,Z7+YP4-5复合菌株的最适温度为37℃,其余各组菌株的最适温度为40℃。原子力显微镜观察到乳酸菌与钙离子结合后表面结构凸起尖锐,与未结合菌株形态差异明显。上述结果表明,钙富集能力最强的单菌株是植物乳杆菌CY1-1,复合菌株是Z7+YP4-5;乳酸菌能有效吸附钙离子在菌体表面进行富集。

In order to screen for lactic acid bacteria with strong calcium conversion and enrichment ability(for subsequent fermentation of fish bone paste),this paper studied the growth ability,acid production ability and calcium accumulation ability of seven lactic acid bacteria(Lactobacillus plantarum CY1-1,Lactobacillus plantarum Z7,Pediococcus pentosaceus DBY2-5-1,Lactobacillus casei D400,Lactobacillus oryzae DL10,Lactobacillus acidophilus DL12,Lactobacillus sake YP4-5)and their composite strains.The effects of calcium ion concentration,growth time,pH,and temperature on the calcium-enrichment capacity of the primary strains were studied,and the differences in the surface structure of the bacteria before and after the enrichment were observed by atomic force microscope,and the morphological changes of lactic acid bacteria and the mechanism of calcium absorption were studied.The results showed that lactic acid bacteria with the highest calcium enrichment were Lactobacillus plantarum CY1-1 and Lactobacillus plantarum Z7.The composite strains with the best enrichment ability were the combination of Lactobacillus plantarum CY1-1 and Lactobacillus acidophilus DL12,Lactobacillus plantarum Z7 and Lactobacillus sake YP4-5.Compared with the single strain,the calcium enrichment in those two composite strains increased by 6.76 and 21.69 mg/g,respectively.The enrichment ability in the stable phase was better than the logarithmic phase,the optimal concentration of calcium ion was 1.2 mg/mL,the optimal pH of Z7 was 6,Z7+YP4-5,CY1-1,and CY1-1+DL12 were 7.2,the optimal temperature of the Z7+YP4-5 group was 37℃,the remaining groups were 40℃.Atomic force microscopy observed significant differences in the cell surface structure before and after calcium enrichment by lactic acid bacteria.The above results showed that the single strain with the strongest calciumaccumulating ability was Lactobacillus plantarum CY1-1,and the composite strain were Z7+YP4-5;lactic acid bacteria could effectively adsorb calcium ions on the surface of the bacteria.