野生银鲳消化道内潜在产酶益生菌产酶条件的初步研究

摘要

采用酶学分析法研究了单因子（温度、pH、发酵时间）变化对野生银鲳（Pampus argenteus）消化道内同时分泌蛋白酶、淀粉酶、纤维素酶和脂肪酶中两种以上的5株菌株产酶活力的影响，即通过测定酶活力的大小找到每株菌最适产酶条件范围。结果显示，在温度31～37℃、pH 7～8、发酵时间3 d的条件下，5株产酶菌的蛋白酶活力最大；在不同温度和pH条件下，5菌株分泌的淀粉酶活力各不相同，但都随发酵时间的延长而增大，3～5 d达最大值；4株分泌纤维素酶的菌株纤维素酶活力受环境影响总体变化不大，在温度31～37℃、酸性条件（pH 5）和发酵时间4 d的条件下为活力最大；2株分泌脂肪酶的菌株在28～31℃、中性（pH 7）、发酵时间1 d条件下其脂肪酶活力最大，最大可接近180 U·mL－1，但活力都随发酵时间而显著下降。结果表明，不同产酶菌所分泌的消化酶活力所需的最适条件有很大不同，了解和掌握银鲳肠道中菌群的产酶条件，对开发潜在产酶益生菌有着积极的作用。%In this study,the effects of single factor variation (temperature,pH and fermentation time)on activities of two or more enzymes,including protease,amylase,cellulose and lipase produced simultaneously by enzyme-producing bacteria in the digestive tract of wild silver pomfret (Pampus argenteus)were measured using the method of enzymatic analysis.The aim is to find the optimum range of fermentation conditions for each strain by measuring the enzyme activity by different media,different incubation temperatures,pH and fermentation time.Results showed that the activities of protease produced by five strains of enzyme-producing bacteria were the highest in the conditions of temperature 3 1 -37 ℃,pH 7 -8 and fermentation time 3 d. The activities of cellulose produced by four cellulose-producing bacteria were not affected significantly by environmental conditions;the enzyme activity was the lowest among all enzymes,and reached the maximum in the conditions of temperature 3 1 -37 ℃,pH 5 and fermentation time 4 d.The activities of lipase produced by four lipase-producing bacteria reached the maximum (180 U·mL-1 )in the conditions of temperature 28-31 ℃,pH 7 and fermentation time 1 d,and declined with the increasing fermentation time.These results indicated that the optimum conditions for enzyme-producing bacteria secreting enzymes with the highest activities were significantly different.Understanding and grasping the enzyme-producing conditions of bacteria in the gut of Pampus argenteus could help to exploite potential enzymes-producing probiotics.