阿魏酸降解放线菌的筛选及其降解与拮抗效果研究

【目的】筛选用于降解西瓜根泌自毒物质阿魏酸的放线菌,研究其降解与拮抗效果。【方法】以127株放线菌为供筛菌株,采用液体发酵培养法筛选阿魏酸降解放线菌,并研究放线菌对阿魏酸的降解率及对西甜瓜枯萎病菌等病原菌的拮抗性。【结果】①从127株供试放线菌中筛选出了编号为25,28及Z30的3株放线菌,在纯培养条件下,以阿魏酸为惟一碳源时,25、28、Z30 3株放线菌对阿魏酸均有较好的降解效果,降解率分别为94.3%,92.6%和90.1%。②在以阿魏酸、淀粉为混合碳源时,3株放线菌对阿魏酸均有较强的降解作用,降解率最高达100%。③纯细胞培养时,3株放线菌对阿魏酸仅有微弱的降解效果。④3株放线菌对西甜瓜枯萎病菌有较强的拮抗作用。【结论】筛选的3株放线菌具有降解西瓜自毒物质阿魏酸及拮抗西甜瓜枯萎病菌的双重功能。

阿魏酸降解菌对木质纤维素水解的增效作用

碱预处理是制备生物乙醇过程中不可缺少的过程。然而,在预处理过程中会产生以阿魏酸为主的毒性抑制物,从而影响木质纤维素的水解效率。该文从土壤中筛选出一株高效阿魏酸降解菌HHQ-1,经鉴定为寡养单胞菌属。将HHQ-1在线添加至纤维素碱预处理水解液中,构建阿魏酸降解菌-里氏木霉纤维素降解菌双菌协同降解体系,并研究其对纤维素水解的提升效果。结果表明,60 h时双菌协同降解体系和单菌降解体系的还原糖产量同时达到最高值。双菌降解体系下还原糖产量为221.33 mg/L,比单菌降解体系提高了7.84%。归其原因为阿魏酸降解菌定向脱除了阿魏酸,降低了毒性物质对纤维素水解过程的影响。

Biodegradation of ferulic acid by a newly isolated strain of Cupriavidus sp. B-8

As a major component of lignin and abundantly existing in softwood and hardwood, ferulic acid has been used as a lignin-related compound for lignin biodegradation study. Biodegradation of ferulic acid by Cupriavidus sp. B-8, a newly isolated strain, was studied. This strain is able to utilize a wide range of lignin-related aromatic compounds as the sole carbon and energy source, including guaiacol, veratric acid, vanillic acid, cinnamic acid, p-coumaric acid, ferulic acid, and sinapic acid. In addition, the effects of different concentrations of ferulic acid on growth of Cupriavidus sp. B-8 were studied. The growth of Cupriavidus sp. B-8 is better under the condition of lower concentration. High-performance liquid chromatography （HPLC） analysis reveals that above 95% of ferulic acid is degraded within 12 h by Cupriavidus sp. B-8. Based on identification of biodegradation intermediates and further metabolites, the biodegradation pathway of ferulic acid by Cupriavidus sp. B-8 was proposed. Ferulic acid is initially converted to 4-vinylguaiacol, and further oxidized to vanillic acid and protocatechuic acid.