The Guts of Herbivorous Invertebrates: Promising Sources of Diverse Microorganisms with Unique Hemicellulolytic Systems

Invertebrates including insects are heterotrophic organisms and widely distributed in ecosystems. Due to their superior ability to digest various types of plant biomass taken as foods, some herbivorous invertebrates have attracted a great deal of industrial attention because such organisms include diverse cellulolytic and hemicellulolytic symbionts in their gut. Recent studies have shown that some of gut microorganisms of herbivores possess one or more extracellular fibrolytic enzymes with unique functions, which can be exploited as useful biocatalysts in various bioindustrial fields. Specifically, microbial hemicellulases with favorable biocatalytic activities are expected to be used for the development of excellent animal feed additives, production of prebiotics such as xylo‐ and mannooligosaccharides, and pretreatment of lignocellulosic biomass for the preparation of fermentable sugars. Here, we review our recent studies accomplished on several hemicellulolytic bacteria isolated from the guts of invertebrates and their glycoside hydrolases such as endo‐β‐1,4‐xylanases and endo‐β‐1,4‐mannanases.