In this study, three psychrotolerant phenol-degrading yeast strains Candida subhashii (strain A011), Candida oregonenis (strain B021) and Schizoblastosporion starkeyi-henricii (strain L012) isolated from Rucianka peatland were examined to determine which alternative metabolic pathway for phenol biodegradation is used by these microorganisms. All yeast strains were cultivated in minimal salt medium supplemented with phenol at 500, 750 and 1,000 mg l-1 concentration with two ways of conducting phenol biodegradation experiments: with and without the starving step of yeast cells. For studied yeast strains, no catechol 2,3-dioxygenase activities were detected by enzymatic assay and no products of catechol meta-cleavage in yeast cultures supernatants (GC-MS analysis), were detected. The detection of catechol 1,2-dioxygenase activity and the presence of cis,cis-muconic acid in the analyzed samples revealed that all studied psychrotolerant yeast strains were able to metabolize phenol via the ortho-cleavage pathway. Therefore, they may be tested in terms of their use to develop biotechnology for the production of cis,cis-muconic acid, a substrate used in the production of plastics (PET) and other valuable goods.

中文翻译：

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从 Rucianka 泥炭地分离出的三种耐冷酵母（Candida subhashii A011、Candida oregonensis B021 和 Schizoblastosporion starkeyi-henricii L012）中苯酚生物降解途径的测定

在这项研究中，检查了从 Rucianka 泥炭地分离的三种耐冷酚降解酵母菌株 Candida subhashii（菌株 A011）、俄勒冈假丝酵母（菌株 B021）和 Schizoblastosporion starkeyi-henricii（菌株 L012），以确定用于苯酚生物降解的替代代谢途径通过这些微生物。所有酵母菌株都在补充有 500、750 和 1,000 mg l-1 浓度的苯酚的基本盐培养基中培养，采用两种方法进行苯酚生物降解实验：有和没有酵母细胞饥饿步骤。对于所研究的酵母菌株，酶促测定未检测到儿茶酚 2,3-双加氧酶活性，并且在酵母培养物上清液中未检测到儿茶酚元裂解产物（GC-MS 分析）。儿茶酚1的检测，2-双加氧酶活性和分析样品中顺式、顺式粘康酸的存在表明，所有研究的耐冷酵母菌株都能够通过邻位裂解途径代谢苯酚。因此，可以对它们的用途进行测试，以开发用于生产顺式、顺式-粘康酸的生物技术，这是一种用于生产塑料 (PET) 和其他有价值产品的底物。