The secretion of extracellular enzymes by soil microbes is rate-limiting in the recycling of biomass. Fungi and bacteria compete and collaborate for nutrients in the soil, with wide ranging ecological impacts. Within soil microbiota, the Bacteroidetes tend to be a dominant phylum, just like in human and animal intestines. The Bacteroidetes thrive because of their ability to secrete diverse arrays of carbohydrate-active enzymes (CAZymes) that target the highly varied glycans in the soil. Bacteroidetes use an energy-saving system of genomic organization, whereby most of their CAZymes are grouped into Polysaccharide Utilization Loci (PULs). These loci enable high level production of specific CAZymes only when their substrate glycans are abundant in the local environment. This gives the Bacteroidetes a clear advantage over other species in the competitive soil environment, further enhanced by the phylum-specific Type IX Secretion System (T9SS). The T9SS is highly effective at secreting CAZymes and/or tethering them to the cell surface, and is tightly coupled to the ability to rapidly glide over solid surfaces, a connection that promotes an active hunt for nutrition. Although the soil Bacteroidetes are less well studied than human gut symbionts, research is uncovering important biochemical and physiological phenomena. In this review, we summarize the state of the art on research into the CAZymes secreted by soil Bacteroidetes in the contexts of microbial soil ecology and the discovery of novel CAZymes for use in industrial biotechnology. We hope that this review will stimulate further investigations into the somewhat neglected enzymology of non-gut Bacteroidetes.

土壤微生物对细胞外酶的分泌是限制生物质循环的速率。真菌和细菌竞争和协作以获取土壤中的养分，并具有广泛的生态影响。在土壤微生物区系中，拟杆菌属往往是优势种群，就像在人和动物的肠道中一样。拟杆菌属之所以能蓬勃发展，是因为它们能够分泌针对土壤中多种多样的聚糖的多种碳水化合物活性酶（CAZymes）。拟杆菌属利用基因组组织的节能系统，从而将它们的大部分酶转化为多糖利用位点（PULs）。仅当它们的底物聚糖在本地环境中丰富时，这些基因座才能够高水平生产特定的CAZyme。这使得拟杆菌属在竞争性土壤环境中具有明显优于其他物种的优势，并且通过特定门类的IX型分泌系统（T9SS）进一步增强了拟杆菌的优势。T9SS在分泌CAZyme和/或将它们束缚到细胞表面方面非常有效，并且与快速滑过固体表面的能力紧密相连，这种连接促进了对营养的主动寻找。尽管土壤拟杆菌属的研究不及人类肠道共生体，但研究发现重要的生化和生理现象。在这篇综述中，我们总结了在微生物土壤生态学的背景下研究土壤拟杆菌分泌的CAZymes的最新技术以及用于工业生物技术的新型Cazymes的发现。