三硝酸丙三酯对厌氧真菌和甲烷菌代谢产物、纤维水解酶活性及菌群丰度的影响

Effects of nitroglycerin on the metabolic profile, fibrolytic enzyme activities and microbial abundance of anaerobic fungi and methanogens

摘要:

【背景】近年来硝酸酯化合物抑制瘤胃甲烷生成的能力受到广泛关注，但鲜有研究关注其对瘤胃内主要纤维降解菌——厌氧真菌的影响。【目的】研究三硝酸丙酸酯(Nitroglycerin NG)对厌氧真菌和甲烷菌活性和代谢的影响。【方法】利用厌氧真菌(Piromyces sp. F1)纯培养及与甲烷菌共培养(Piromyces sp. F1+ Methanobrevibacter sp.)，比较不同剂量NG (0.0、6.6、13.2和19.8?μmol/L)对厌氧真菌和甲烷菌的代谢终产物、主要纤维水解酶活性及菌群丰度的影响。【结果】厌氧真菌共培养组中，6.6 μmol/L NG完全抑制了甲烷的生成，积累了氢气和甲酸(P<0.05)，降低了乙酸浓度以及木聚糖酶和羧甲基纤维素酶活性(P<0.05)，但未显著影响厌氧真菌和甲烷菌的丰度(P>0.05)。厌氧真菌纯培养组中，6.6 μmol/L NG显著降低了甲酸、乙酸、乙醇、木聚糖酶和羧甲基纤维素酶活性(P<0.05)，但总产气量和氢气产量没有显著差异(P>0.05)。在2个培养体系中，随着剂量的升高，NG对厌氧真菌和甲烷菌的抑制增强。【结论】NG能够抑制甲烷菌的活性，但对厌氧真菌也有抑制作用。

Abstract:

[Background] In recent years, the ruminal methane mitigation potential of nitrooxy compounds has attracted a wide attention, however, limited information is available for the effect of these compounds on anaerobic fungi, an important fibrolytic microorganism in the rumen. [Objective] To investigate the effects of nitroglycerin (NG) on the activity and metabolism of anaerobic fungi and methanogens. [Methods] The fungal mono-cultures (Piromyces sp. F1) and co-cultures with methanogens (Piromyces sp. F1+Methanobrevibacter sp.) were used. A series of doses of NG (0.0、6.6、13.2 and 19.8 μmol/L) were added in these cultures and the metabolic profile, fibrolytic activities and microbial abundances were comparably analyzed. [Results] In co-cultures, the dose of 6.6 μmol/L NG completely inhibited the methane production, resulting in the accumulation of hydrogen and formate (P<0.05). And the acetate production and the activities of xylanase and carboxymethyl cellulase decreased (P<0.05), while the changes of the abundances of anaerobic fungi and methanogens were not observed (P>0.05). In fungal mono-cultures, the dose of 6.6 μmol/L NG decreased the production of formate, acetate and ethanol as well as the activities of xylanase and carboxymethyl cellulase (P<0.05), while did not affect the total gas and hydrogen production (P>0.05). In the two culture systems, as the dosage of NG increased, the inhibitory effect on anaerobic fungi and methanogens was enhanced. [Conclusion] NG had inhibitory effect on methanogens, but also had negative effect on anaerobic fungi.