An application of wastewater treatment in a cold environment and stable lipase production of Antarctic basidiomycetous yeast Mrakia blollopis.
An application of wastewater treatment in a cold environment and stable lipase production of Antarctic basidiomycetous yeast Mrakia blollopis.
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DOI：
10.1371/journal.pone.0059376
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发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Hoshino T
中科院分区：
文献类型：
--
作者：
Tsuji M;Yokota Y;Shimohara K;Kudoh S;Hoshino T
污水中的乳脂凝块是低温条件下活性污泥处理的耐火材料之一。为了使用生物修复剂解决这个问题，我们筛选了南极酵母，并从东南极洲斯卡夫内斯湖纳加伊克沉积物的藻垫中分离出SK-4菌株。该酵母菌株在 ITS 和 D1/D2 序列中与 Mrakia bllolopis CBS8921T 显示出高度的核苷酸序列同源性 (>99.6%)，并且在应用于活性污泥时具有两个独特的特征；即，它显示出利用各种碳源并在无维生素条件下生长的潜力。事实上，它的生化需氧量 (BOD) 去除率比对照高 1.25 倍。我们认为，应用SK-4菌株提高BOD去除率是基于其脂肪酶活性和特性。最后，我们从SK-4中纯化了脂肪酶，发现该酶在很宽的温度和pH范围内，甚至在各种金属离子和有机溶剂存在下都非常稳定。因此，SK-4 是一种很有前途的生物修复剂，可在低温条件下清除乳制品废水中不需要的乳脂凝块。
Milk fat curdle in sewage is one of the refractory materials for active sludge treatment under low temperature conditions. For the purpose of solving this problem by using a bio-remediation agent, we screened Antarctic yeasts and isolated SK-4 strain from algal mat of sediments of Naga-ike, a lake in Skarvsnes, East Antarctica. The yeast strain showed high nucleotide sequence homologies (>99.6%) to Mrakia blollopis CBS8921T in ITS and D1/D2 sequences and had two unique characteristics when applied on an active sludge; i.e., it showed a potential to use various carbon sources and to grow under vitamin-free conditions. Indeed, it showed a biochemical oxygen demand (BOD) removal rate that was 1.25-fold higher than that of the control. We considered that the improved BOD removal rate by applying SK-4 strain was based on its lipase activity and characteristics. Finally, we purified the lipase from SK-4 and found that the enzyme was quite stable under wide ranges of temperatures and pH, even in the presence of various metal ions and organic solvents. SK-4, therefore, is a promising bio-remediation agent for cleaning up unwanted milk fat curdles from dairy milk wastewater under low temperature conditions.