A research team led by Prof. LI Dejun from the Institute of Subtropical Agriculture of the Chinese Academy of Sciences has made significant strides in using synthetic microbial communities (SynCom) to enhance lignocellulose degradation, improve compost transformation, and promote crop growth. 

Their latest findings provide new insights into sustainable agriculture and were published across three recent studies.

In modern agriculture, composting serves as an environmentally friendly method for processing agricultural waste, converting organic waste into fertilizers and improving soil quality. The application of SynCom, particularly in the degradation of lignocellulose, has gradually become a key strategy to enhance composting efficiency. At the same time, the health of crops is closely related to the balance of soil microbial communities. SynCom can regulate the rhizosphere microbiota, enhancing nutrient absorption and stress resistance in crops, thus promoting crop growth and disease resistance. 

The team first uncovered key mechanisms by which SynCom promotes lignocellulose degradation during the thermophilic phase of composting. Inoculation with SynCom significantly reduced lignin, cellulose, and hemicellulose content, while boosting activities of crucial degradation enzymes such as laccase, manganese peroxidase, cellulase, and xylanase.

Additionally, metagenomic analysis showed that synthetic microbial communities significantly enhanced microbial metabolic pathways related to carbohydrate metabolism, amino acid metabolism, vitamin metabolism, and energy metabolism, thereby optimizing the structure and function of the microbial community at the gene level during composting. 

Moreover, SynCom further enhance compost material transformation by regulating fungal communities. The researchers found that SynCom inoculation increased the relative abundance of key fungal genera such as Cephaliophora and Thermomyces, and significantly increased the activity of functional groups closely related to lignocellulose degradation, including wood-decaying fungi, undefined saprophytic fungi, and leaf litter-decomposing fungi. 

Furthermore, the significant enrichment of the key species Hydropisphaera (OTU10) was confirmed as an important driver for lignocellulose degradation, significantly improving the quality of organic fertilizer after compost maturity. 

Additionally, the researchers further explored the application of synthetic microbial communities in promoting pepper growth. SynCom inoculation significantly increased the plant height, stem diameter, leaf number, chlorophyll content, and root vitality of pepper plants. High-throughput sequencing results showed that SynCom inoculation significantly increased the richness of rhizosphere microbial communities and the abundance of key genera, especially the relative abundance of Sordariomycetes and Pseudarthrobacter, which were closely correlated with crop growth. 

Collectively, these studies highlight synthetic microbial community inoculation as an effective, environmentally friendly approach to agricultural waste management and crop yield enhancement. The findings offer promising new strategies and technical foundations for advancing sustainable agriculture. 

As research into SynCom deepens, their potential in optimizing composting and agricultural production will be increasingly realized, playing a significant role in promoting the development of green agriculture.

Mechanisms of synthetic microbial community inoculation in enhancing lignocellulose degradation during the thermophilic phase of composting (Image by CHEN Shuangshuang)

Mechanisms of synthetic microbial community inoculation in promoting lignocellulose degradation (Image by LIU Qiumei)

Mechanisms of synthetic microbial community inoculation in promoting pepper growth(Imaged by YOU Tian and LIU Qiumei)