不同比例油茶饼粕自然发酵过程中的养分变化及微生物群落比较

Comparison of nutrient changes and bacterial community during natural fermentation of Camellia oleifera oil-tea cake with different proportions

【目的】为比较分析油茶饼粕在土壤自然发酵过程中养分和微生物群落组成变化。【方法】以含已脱茶皂素油茶饼粕为材料,通过不同比例(0、5%、10%、20%和100%)混合在土壤中开展自然发酵试验,分析其在不同时间段(1、2、4、8和12周)的养分变化以及通过细菌16S rRNA基因高通量测序比较第4周时茶粕中微生物群落组成。【结果】不同比例的油茶饼粕全氮和有机质含量随着时间的推移总体变化呈下降趋势,100%茶粕处理组变化相对平稳,各时间段间的差异性不显著;5%、20%和100%处理组的C/N均于试验第1周和第2周达到最高值,分别为34.3、35.1和32.3,之后呈下降趋势。100%处理组的腐殖酸含量也于第1周时达到最高值26%。随着茶粕含量的增加,科层级的OTUs数量呈现先降后升再降的趋势,在10%和20%处理组的OTUs数分别为231和227,而到100%处理组则为150。20%处理组的细菌多样性高于其他处理组,COG功能预测显示其主要在第一层级的氨基酸的运输和代谢、转录、碳水化合物运输和代谢,各功能占比在6%~8%之间。【结论】茶粕在自然环境发酵中于第1周全氮、有机质和腐殖酸均发生明显变化,并于第4周往后趋于稳定,此时间点可以作为茶粕有机肥发酵的关键工艺点,茶粕在20%含量时显示出更好的微生物多样性,并且在发酵过程中噬几丁质菌科、鞘脂单胞科、黄单胞菌科的相对丰度均较高。

【Objective】To compare and analyze the changes of nutrients and microbial community composition of Camellia oleifera oil-tea cake during natural fermentation.【Method】Natural fermentation experiments were carried out in soil with different proportions(0,5%,10%,20%and 100%)of oil-tea cake.The nutrient changes of oil-tea cake after different time periods(1 week,2 weeks,4 weeks,8 weeks and 12 weeks)were analyzed,and the microbial community composition at the fourth week was compared by bacterial 16S rRNA gene high-throughput sequencing.【Result】The contents of total nitrogen and organic matter in different proportions of C.oleifera oil-tea cake showed a downward trend,and the changes in the 100%tea cake treatment group were relatively stable,there was no significant difference in each time period;the C/N of 5%,20%and 100%treatment groups reached the highest value in the first and second weeks of the experiment,which were 34.3,35.1 and 32.3 respectively,and then showed a downward trend.The humic acid content of 100%treatment group also reached the highest value of 26%in the first week.With the increase of tea cake content,the number of OTU at the family level decreased first,then increased and then decreased.In the 10%and 20%treatment groups,it was 231 and 227 respectively,while at 100%,it was 150.The microbial diversity of 20%treatment group was significantly higher than that of other treatment groups.The prediction of COG function showed that it was mainly in the first level of amino acid transport and metabolism,transcription,carbohydrate transport and metabolism,and each function accounted for 6%-8%.【Conclusion】The total nitrogen,organic matter and humic acid of oil-tea cake changed significantly in the first week of natural environment fermentation,and leveled off after the fourth week.This time point could be used as the key process point of tea meal fermentation,and tea cake showed better microbial diversity at 20%.The relative abundance of Chitinophagidae,Sphingomonas and Xanthomonidae were higher.