生物降解植物甾醇菌株的选择。

Selection of Biodegrading Phytosterol Strains.

机构信息

Microbiology Department, University of Concepción, Concepción, Chile.

Water Research Center for Agriculture and Mining (CRHIAM), ANID Fondap Center, Victoria, Concepción, Chile.

出版信息

Methods Mol Biol. 2023;2704:43-50. doi: 10.1007/978-1-0716-3385-4_3.

DOI:10.1007/978-1-0716-3385-4_3

PMID:37642837

Abstract

The phytosterol-biotransforming strains can be selected from Mycobacterium sp. using a high concentration of β-sitosterol. The selection is made by culturing the strains in a medium enriched with 14 g/L of β-sitosterol as the unique source of carbon. During 2 months, the bacterial cultures are transferred successively. The extraction of the biotransformation products is made with methanol and ethyl acetate. The qualitative and quantitative analyses are made by means of thin-layer chromatography, gas-liquid chromatography (GLC), and GLC-mass spectrometry. Under these conditions, it is observed that after seven transfers, the strains Mycobacterium sp. MB-3683 and Mycobacterium fortuitum B-11045 increase their biotransformation capacity from 20% to 64% and from 34% to 55%, respectively. The products in the highest proportion identified for each trial are androstenedione and androstadienedione. The results suggest that the high substrate concentration could be a selective mechanism to obtain strains more efficient in the biotransformation of β-sitosterol into steroidal bases.

摘要

可以从分枝杆菌属（Mycobacterium sp.）中选择利用高浓度β-谷甾醇进行生物转化的菌株。通过在含有 14g/Lβ-谷甾醇的培养基中培养这些菌株，以β-谷甾醇作为唯一的碳源进行选择。在 2 个月的时间里，连续进行细菌培养的转接。用甲醇和乙酸乙酯提取生物转化产物。通过薄层色谱法、气相色谱（GLC）和 GLC-质谱法进行定性和定量分析。在这些条件下，观察到经过七次转接后，分枝杆菌属（Mycobacterium sp.）MB-3683 和偶发分枝杆菌（Mycobacterium fortuitum）B-11045 的生物转化能力分别从 20%增加到 64%和从 34%增加到 55%。每种试验中鉴定出的比例最高的产物是雄烯二酮和雄甾烯二酮。结果表明，高底物浓度可能是获得更有效地将β-谷甾醇生物转化为甾体碱的菌株的选择性机制。