Insect Gut Microbiota as a Reservoir of Industrially Relevant Enzymes: A Comprehensive Review.

The insect gut microbiome constitutes a substantial yet underexplored reservoir of microbial diversity with important implications for entomology and biotechnology. Gut-associated microbes are crucial for maintaining host physiology, encompassing digestion, nutrient absorption, immune function, and resistance to environmental stress. In addition to these biological functions, the insect gut contains metabolically versatile bacteria that can synthesise a variety of bioactive substances, including amino acids, vitamins, antimicrobial agents and a wide range of industrially important enzymes. Enzymes such as cellulases, amylases, proteases, lipases etc., isolated from insect gut microbes have attracted increasing attention owing to their stability, versatility and facilitation of optimisation for large-scale production. Insects, being able to thrive in extreme environments, possess gut-derived enzymes that demonstrate exceptional stability and catalytic effectiveness, rendering them suitable for industrial and biotechnological applications. The current review compiles contemporary findings on enzyme-producing gut bacteria from various insect orders, emphasising the main enzyme classes identified, potential microbial species, traditional as well as advanced screening methodologies for important enzymes reported, viz., cellulases, proteases, amylases and their multifaceted applications in bioconversion, bioremediation and other industrial domains.