一株异养型细菌对无机硫化物的降解特性和培养条件优化

Characterization and optimization of a heterotrophic bacterium for sulfide degradation

摘要:

畜禽屠宰加工、鱼粉饲料加工等一些食品工业生产过程中会释放出大量的硫化氢恶臭气体，导致周边环境的严重污染。为实现以培养异养型细菌脱除硫化氢气体的目的，取分离到的异养脱硫细菌XJ-2，通过诱变筛选得到一株高效脱硫菌株ZJNB-B3，其脱硫率达97%。基于形态学研究、API 50 CHB生理生化鉴定及16S rRNA基因测序，鉴定该菌为蜡状芽胞杆菌Bacillus cereus ZJNB-B3。该菌GenBank登录号为MF679650。降解特性研究表明，ZJNB-B3菌株对有毒的硫化物有较高耐受性，耐受上限高达300 mg/L。采用响应面法优化环境因素对菌株降解硫化物效率的影响，得到在最适培养温度30 ℃下，初始S2–浓度为211.8 mg/L、初始pH值6.72、接种量为5.04%时，菌株氧化脱硫效果最显著，经过实测在48 h产生的硫酸盐浓度为63.8 mg/L，脱硫率达97.3%。菌株在氧化硫化物时不会产生硫酸抑制菌株的生长，可以在pH值温和的环境条件下脱硫，因此，该菌有较高的工业应用价值。本研究为异养型细菌应用于工业反应器脱除硫化氢恶臭气体提供了小试研究基础。

Abstract:

The emission of hydrogen sulfide in the waste gas from slaughter plant, fishmeal feed processing and some other food industrial processing could cause serious air pollution to the surrounding environment. The purpose of this study was to screen heterotrophic bacterium strains for the removal of hydrogen sulfide odor. One heterotrophic bacterial mutant ZJNB-B3 was derived from the sulfide degrader?Bacillus cereus XJ-2 and its sulfide removal efficiency was 97%. Based on the morphology studies, biochemical tests and 16S rRNA gene analysis, the strain was identified as Bacillus cereus ZJNB-B3. The NCBI GenBank accession number is MF679650. Batch tests showed that the strain tolerated up to 300 mg/L of toxic S2– concentration. Response surface methodology was applied to optimize the conditions of degradation of sulfide. The optimal parameters were as follows: initial sulfide concentration 211.8 mg/L, initial pH 6.72, inoculum volume 5.04%, and incubation temperature 30 ℃. The accumulated sulfate concentration was 63.8 mg/L and the sulfide removal efficiency was 97.3% after 48 h incubation. No sulfuric acid was generated during sulfide oxidation by the strain. Sulfide could be removed effectively by this strain under mild pH conditions. The results suggested that the strain may have great industrial application potential. This study provides the fundamentals for the removal of hydrogen sulfide gas.