Bioprospecting lipase producers in non-conventional habitats are the way to find special enzymes of diverse applications. Halo-alkaline marshes in Wadi El Natrun in Egypt are some of the most stable ecological systems in the world, and because of the double extremities of alkalinity and salinity, they harbor individual microbes capable of adapting stress conditions. Eight strains were recovered from the coastline soil of Al-Beida Lake in Wadi El Natrun and have been tested for lipase production. Among the eight isolates, the strain SBLWN_MH2 was the most active producer of lipase (7.5 U/ml). The crude SBLWN_MH2 lipase showed activity over a wide pH range (3.5 to 13) with an optimum pH at 10.5, and it was able to show more than 75% of its highest activity at pH elevated up to 13. The identification using phenotypic and genotypic methods strongly indicated that the strain SBLWN_MH2 belonged to the genus Streptomyces with a similarity of 99%. Thus, it has been given the suggested name Streptomyces sp. SBLWN_MH2 (MG593538). SBLWN_MH2 produced extracellular lipase in modified starch casein medium supplemented with different oils or Tween-80, and the potential production rate has been attained in the case of linseed oil after 3 days. Further experiments have been carried out to optimize medium composition through Box-Behnken design and response surface methodology, and it was possible to achieve more than 3.5-fold increase in lipase production. The present study indicates that Streptomyces sp. SBLWN_MH2 is a potential lipase producer and could be fruitfully employed in the large-scale production of highly alkaline lipase.

中文翻译：

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从 Wadi El Natrun 的卤碱性栖息地分离的新产脂肪酶链霉菌：酶生产的多相鉴定和统计优化

在非常规栖息地进行生物勘探脂肪酶生产商是寻找具有不同应用的特殊酶的途径。埃及 Wadi El Natrun 的光环碱性沼泽是世界上最稳定的生态系统之一，由于具有碱度和盐度的双重特性，它们拥有能够适应压力条件的个体微生物。从 Wadi El Natrun 的 Al-Beida 湖海岸线土壤中回收了 8 株菌株，并进行了脂肪酶生产测试。在八个分离株中，菌株 SBLWN_MH2 是最活跃的脂肪酶生产者 (7.5 U/ml)。粗制 SBLWN_MH2 脂肪酶在较宽的 pH 范围（3.5 至 13）内显示活性，最适 pH 为 10.5，并且在 pH 升高至 13 时能够显示其最高活性的 75% 以上。使用表型和基因型方法的鉴定强烈表明菌株SBLWN_MH2属于链霉菌属，相似度为99%。因此，它被赋予了建议的名称 Streptomyces sp。SBLWN_MH2 (MG593538)。SBLWN_MH2在添加不同油或Tween-80的改性淀粉酪蛋白培养基中产生细胞外脂肪酶，3天后在亚麻籽油的情况下已达到潜在产率。通过 Box-Behnken 设计和响应面方法进行了进一步的实验以优化培养基组成，并且有可能将脂肪酶产量提高 3.5 倍以上。本研究表明链霉菌属。SBLWN_MH2 是一种潜在的脂肪酶生产者，可以有效地用于高碱性脂肪酶的大规模生产。