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.

中文翻译：

---

甲基营养芽孢杆菌DCS1同时生产碱性淀粉酶和生物表面活性剂：用作洗涤剂添加剂。

这项研究调查了甲基芽孢杆菌共生产碱性淀粉酶和脂肽DCS1菌株及其生化特征。当马铃薯淀粉（10 g / L）和谷氨酸（5 g / L）分别用作碳源和氮源时，淀粉酶和生物表面活性剂的最佳产量。将细菌菌株在25℃和150rpm下温育48小时。如酶谱技术所示，该菌株产生独特的淀粉酶。最适pH和温度分别为60–65°C和8.0。EDTA（5 mM）会部分抑制淀粉酶的活性。马铃薯淀粉的主要水解产物是麦芽糖和麦芽三糖。碱性淀粉酶显示出优异的稳定性和与各种固体和液体洗涤剂的相容性。此外，与碱性淀粉酶同时生产的生物表面活性剂在盐度，pH和温度的不同范围内显示出高稳定性。含有生物表面活性剂和淀粉酶活性的B.甲基营养菌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使用的潜在候选物。