一种厌氧真菌共培养甲烷菌株的分离及其甲烷生产特性解析

Isolation and biomethane production characterization of a novel co-culture of anaerobic fungus and methanogen

摘要:

【背景】开发生物甲烷资源是减轻化石燃料供求紧张的有效措施，而秸秆类原料的预处理及甲烷生产方法需要不断创新，从而进一步满足可持续发展。厌氧真菌与甲烷菌共培养能够通过假根侵入及纤维降解酶双重预处理秸秆并生产甲烷，但目前全世界被报道的骆驼胃肠道来源的厌氧真菌分离培养物仅有1株。【目的】从新疆准噶尔双峰驼瘤胃内容物中分离出新型厌氧真菌和甲烷菌共培养物，研究其在降解秸秆并联合生产生物甲烷方面的应用潜力。【方法】采用Hungate滚管纯化技术将从骆驼胃肠道中分离的厌氧真菌和甲烷菌共培养，对其进行形态学及分子学鉴定，随后厌氧发酵5种底物(稻秸、芦苇、构树叶、苜蓿秆和草木樨)，研究产甲烷量、降解效果及主要代谢产物等方面的特性。【结果】筛选到的共培养物中的厌氧真菌为Oontomyces sp. CR1，甲烷菌为Methanobrevibacter sp. CR1。其在降解稻秸时表现出最高的木聚糖酶酶活力(21.64 IU/mL)及甲烷产量(143.39 mL/g-DM)，甲烷生产特性较分离自其他动物宿主的厌氧真菌共培养物更优。【结论】共培养厌氧真菌与甲烷菌菌株CR1是一种新型高效降解菌株资源，其在利用木质纤维素生物质生产生物甲烷方面具有良好的应用前景。

Abstract:

[Background] Exploiting biomethane resources is an effective way to alleviate the shortage of fossil fuel supply nowadays. At the same time, the methods of lignocellulosic biomass pretreatment and methane production need to be innovated for sustainable development. The co-cultivation of anaerobic fungi and methanogens enables dual pretreatment of lignocellulosic biomass and methane production by rhizoid invasion and fiber-degrading enzymes. However, only one culture of anaerobic fungi isolated from camel gut has been reported in the world. [Objective] To isolate and identify the novel co-culture of anaerobic fungus and methanogen from the rumen contents of Xinjiang Bactrian camels, and investigate its application potential in degrading lignocellulosic biomass and producing biomethane. [Methods] The co-culture of anaerobic fungus and methanogen was isolated by Hungate rolling-tube technique from camel gastrointestinal tract and then identified based on the morphological and molecular characteristics. Further, the biomethane production, degradation efficiency, and primary metabolites of the co-culure were determined by anaerobic fermentation with five substrates (rice straw, reed, Broussonetia papyrifera leaves, alfalfa stalk, and Melilotus officinalis). [Results] The co-culture CR1 of anaerobic fungus and methanogen was composed of Oontomyces sp. CR1 and Methanobrevibacter sp. CR1, which had high xylanase activity (21.64 IU/mL) and biomethane production (143.39 mL/g-DM) when degrading rice straw. Furthermore, CR1 had better methane production property than the anaerobic fungal co-cultures isolated from other animals. [Conclusion] The co-culture CR1 of anaerobic fungus and methanogen is a novel degrading strain with high efficiency, which has a promising application prospect in the production of biomethane from lignocellulosic biomass.