Yu Shiqiang, Li Liuxue, Zhao Huiying, Tu Yan, Liu Ming, Jiang Linshu, Zhao Yuchao
Beijing Key Laboratory of Dairy Cow Nutrition, Animal Science and Technology College, Beijing University of Agriculture, Beijing, China.
Beijing Key Laboratory of Dairy Cow Nutrition, Key Laboratory of Feed Biotechnology of the Ministry of Agriculture and Rural Affairs, Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing, China.
Microbiol Spectr. 2023 Mar 2;11(2):e0351722. doi: 10.1128/spectrum.03517-22.
Rumen microorganisms are promising for efficient bioconversion of lignocellulosic wastes to biofuels and industrially relevant products. Investigating the dynamic changes of the rumen microbial community colonizing citrus pomace (CtP) will advance our understanding of the utilization of citrus processing waste by rumen fluid. Citrus pomace in nylon bags was incubated in the rumen of three ruminally cannulated Holstein cows for 1, 2, 4, 8, 12, 24, and 48 h. Results showed that total volatile fatty acids concentrations and proportions of valerate and isovalerate were increased over time during the first 12 h. Three major cellulose enzymes attached to CtP rose initially and then decreased during the 48-h incubation. Primary colonization happened during the initial hours of CtP incubation, and microbes compete to attach CtP for degrading easily digestible components and/or utilizing the waste. The 16S rRNA gene sequencing data revealed the diversity and structure of microbiota adhered to CtP were distinctly different at each time point. The increased abundance of Fibrobacterota, , and may explain the elevated volatile fatty acids concentrations. This study highlighted key metabolically active microbial taxa colonizing citrus pomace in a 48-h rumen incubation, which could have implications for promoting the biotechnological process of CtP. As a natural fermentation system, the rumen ecosystem of ruminants can efficiently degrade plant cellulose, indicating that the rumen microbiome offers an opportunity for anaerobic digestion to utilize biomass wastes containing cellulose. Knowledge of the response of the microbial community to citrus pomace during anaerobic fermentation will help improve the current understanding of citrus biomass waste utilization. Our results demonstrated that a highly diverse rumen bacterial community colonized citrus pomace rapidly and continuously changed during a 48-h incubation period. These findings may provide a deep understanding of constructing, manipulating, and enriching rumen microorganisms to improve the anaerobic fermentation efficiency of citrus pomace.
瘤胃微生物在将木质纤维素废物高效生物转化为生物燃料和工业相关产品方面具有广阔前景。研究瘤胃微生物群落定殖于柑橘渣（CtP）过程中的动态变化，将有助于我们深入了解瘤胃液对柑橘加工废弃物的利用情况。将尼龙袋中的柑橘渣在三头安装有瘤胃瘘管的荷斯坦奶牛瘤胃中分别培养1、2、4、8、12、24和48小时。结果表明，在最初的12小时内，总挥发性脂肪酸浓度以及戊酸和异戊酸的比例随时间增加。在48小时的培养过程中，附着在CtP上的三种主要纤维素酶先升高后降低。CtP培养的最初几个小时内发生了初次定殖，微生物竞争附着在CtP上以降解易消化成分和/或利用该废弃物。16S rRNA基因测序数据显示，在每个时间点，附着在CtP上的微生物群的多样性和结构明显不同。纤维杆菌门、 、 的丰度增加可能解释了挥发性脂肪酸浓度的升高。本研究突出了在48小时瘤胃培养过程中定殖于柑橘渣的关键代谢活跃微生物类群，这可能对促进CtP的生物技术过程具有重要意义。作为一个天然发酵系统，反刍动物的瘤胃生态系统能够高效降解植物纤维素，这表明瘤胃微生物组为厌氧消化利用含纤维素的生物质废物提供了机会。了解厌氧发酵过程中微生物群落对柑橘渣的反应将有助于增进我们目前对柑橘生物质废物利用的理解。我们的结果表明，一个高度多样化的瘤胃细菌群落迅速定殖于柑橘渣，并在48小时的培养期内持续变化。这些发现可能有助于深入理解构建、操纵和富集瘤胃微生物以提高柑橘渣厌氧发酵效率。
