乙醛降解菌Bacillus velezensis LT-2的发酵条件优化

Optimization of fermentation conditions of an acetaldehyde-degrading bacterium Bacillus velezensis LT-2

摘要:

【背景】乙醛作为醛类污染物广泛存在于生产生活中，相较于传统的物化方法，生物降解具有诸多优势，已成为研究热点。【目的】筛选获得降解乙醛的菌株并优化其发酵条件，为微生物降解乙醛提供试验资源。【方法】经过富集培养和乙醛降解试验获得一株乙醛降解能力高的菌株；通过单因子优化(碳源、氮源、金属离子、温度、转速、接种量和初始pH)和多因子的交互试验(Plackett-Burman试验、最陡爬坡试验和Box-Behnken design试验)考察培养基组分和发酵条件对菌株降解乙醛的影响，并考察菌株在最佳条件下的生长状态和乙醛降解能力。【结果】筛选获得一株具有乙醛降解能力的菌株Bacillus velezensis LT-2，该菌株降解乙醛的最佳培养条件为：蔗糖30 g/L，营养肉汤0.6 g/L，氯化钾0.12 mol/L，温度28 ℃，初始pH 7.5，接种量6%，摇床转速200 r/min。在此条件下，B. velezensis LT-2可在1 g/L乙醛的培养液中生长，22 h的降解率为89.77%±2.33%，是优化前降解率的3.58倍。【结论】试验菌株B. velezensis LT-2对乙醛具有良好的降解效率，为乙醛工业废水的生物治理提供了较好的试验基础和应用依据。

关键词:乙醛;生物降解;条件优化;贝莱斯芽孢杆菌

Abstract:

[Background] As an aldehyde pollutant, acetaldehyde widely exists in production and life. Compared with physical and chemical methods, biodegradation with great advantages has become a research hotspot. [Objective] To provide experimental resources for the microbial degradation of acetaldehyde, we screened out an acetaldehyde-degrading strain and optimized the fermentation conditions for degrading acetaldehyde. [Methods] After enrichment culture and acetaldehyde-degrading experiment, a strain with high acetaldehyde-degrading ability was obtained. Single factor tests (carbon source, nitrogen source, metal ions, temperature, rotational speed, inoculation amount, and initial pH) and multi-factor interaction experiments (Plackett-Burman design, steepest ascent design, and Box-Behnken design) were carried out to study the effects of culture medium components and fermentation conditions on the degradation of acetaldehyde by the strain. The growth curve and acetaldehyde degradation curve of the strain were established. [Results] A strain LT-2 with high acetaldehyde-degrading ability was obtained and identified as Bacillus velezensis LT-2. The optimum parameters for degrading acetaldehyde by B. velezensis LT-2 were fermentation in the medium composed of 30 g/L sucrose, 0.6 g/L nutrient broth, and 0.12 mol/L potassium chloride at 28 ℃, initial pH 7.5, inoculation size of 6%, and 200 r/min. Under the optimal conditions, B. velezensis LT-2 can grew in the medium with 1 g/L acetaldehyde and showed the 22 h acetaldehyde degradation rate of 89.77%±2.33%, which was 3.58 times of that before optimization. [Conclusion] B. velezensis LT-2 was effective in degrading acetaldehyde. This study provides experimental and practical references for the biological treatment of acetaldehyde-containing industrial wastewater.

Key words:acetaldehyde;biological degradation;optimization of fermentation parameters;bacillus velezensis