Laboratoire de Génie Enzymatique et de Microbiologie, Ecole Nationale d'Ingénieurs de Sfax, B.P. "1173", 3038, Sfax, Tunisia.
Biodegradation. 2019 Aug;30(4):247-258. doi: 10.1007/s10532-018-9847-8. Epub 2018 Aug 10.
This study investigated the coproduction of alkaline amylase and lipopeptides by Bacillus methylotrophicus DCS1 strain, as well as their biochemical characterisation. The best production of both amylase and biosurfactant was obtained when potato starch (10 g/L) and glutamic acid (5 g/L) were used as carbon and nitrogen sources, respectively. The bacterial strain was incubated for 48 h at 25 °C and 150 rpm. This strain produced a unique amylase as showed by zymography technique. The optima pH and temperature were 60-65 °C and 8.0, respectively. Amylase activity was partially inhibited by EDTA (5 mM). The main hydrolysis products of potato starch were maltose and maltotriose. The alkaline amylase showed excellent stability and compatibility with various solid and liquid detergents. Furthermore, the biosurfactant, produced simultaneously with alkaline amylase, demonstrated high stability at different ranges of salinity, pH, and temperature. Considering its promising properties, B. methylotrophicus DCS1 crude extract containing both biosurfactants and amylase activity may be considered as a potential candidate for future use in detergent processing industries and environmental remediation processes.
本研究考察了甲基营养芽孢杆菌 DCS1 菌株同时生产碱性淀粉酶和脂肽的情况，并对其生化特性进行了研究。当以马铃薯淀粉（10 g/L）和谷氨酸（5 g/L）分别作为碳源和氮源时，该菌株同时生产两种酶的产量最高。将细菌在 25°C 和 150 rpm 下培养 48 小时。该菌株通过同工酶技术显示产生了一种独特的淀粉酶。最适 pH 和温度分别为 60-65°C 和 8.0。淀粉酶活性部分被 EDTA（5 mM）抑制。马铃薯淀粉的主要水解产物是麦芽糖和麦芽三糖。碱性淀粉酶表现出良好的稳定性和与各种固体和液体洗涤剂的兼容性。此外，与碱性淀粉酶同时产生的生物表面活性剂在不同盐度、pH 值和温度范围内表现出很高的稳定性。考虑到其有前途的特性，含有生物表面活性剂和淀粉酶活性的甲基营养芽孢杆菌 DCS1 粗提物可能被认为是未来在洗涤剂加工行业和环境修复过程中应用的潜在候选物。
