一株大麻脱胶菌株的分离鉴定及其产果胶酶发酵培养基的优化

Isolation and Identification of a Hemp Degumming Strain and the Optimization of Fermentation Medium for Pectinase Production

为了分离和鉴定对大麻有脱胶效果的碱性果胶酶生产菌株,优化其产果胶酶培养基组成,试验选用果胶作为唯一碳源进行菌株筛选,并采用单因素和正交试验筛选果胶酶发酵培养基组成。结果表明:从沤麻水体中分离到14株具有脱胶能力的细菌,其中X-6菌果胶酶产量最高,该菌革兰氏阴性,大小为0.6~0.8μm×2~3μm,据其生理生化特征和16SrDNA鉴定,该菌株鉴定并被命名为产碱假单胞菌X-6(Pseudomonas alcaligenes X-6),该菌的最佳产果胶酶培养基组成为葡萄糖5g/L,马铃薯淀粉4g/L,酵母粉4g/L,玉米浆4g/L,氯化钙1.5g/L,氯化钠0.5g/L,经验证在该条件下果胶酶活力达到586U/mL,采用发酵后的粗酶液对大麻进行脱胶试验,残胶率由38.9%降低至17.2%,脱胶效果较好。试验分离和鉴定出一株对大麻脱胶效果较好的菌株,并获得其产果胶酶发酵培养基。

A strain for hemp degumming was isolated and identified, and composition of fermentation medium for pectinase production was optimized. Pectin plate was used to screen the pectinase production strain, and single factor and orthogonal experiments were performed to optimize the fermentation medium composition. Fourteen bacteria with pectinase production capacity were isolated, of which the strain X-6 had the highest pectinase activity. The Gram stain showed negative, and its cell size was 0.6~0.8×2~ 3 μm. According to its physiological, biochemical characteristics and 16S rDNA, the strain was identified and named as Pseudomonas alcaligenes X-6. The optimum medium composition for pectinase production was glucose 5 g/L, potato starch 4 g/L, yeast powder 4 g/L, corn pulp 4 g/L, calcium chloride 1.5 g/L and sodium chloride 0.5 g/L. Under the condition, the pectinase activity was 586 U/mL. The test of hemp degumming was carried out using the fermented crude enzyme solution. The degumming effect was the best with gum residue reduced from 38.9% to 17.2%. A strain with the best degumming effect for hemp was isolated and identified, and the fermentation medium for pectinase production was optimized.