Microbial Conversion of Inulin to Valuable Products: The Biorefinery Concept

The global transition to a sustainable bioeconomy requires the engagement of renewable and cost-effective substrates to obtain valuable bio-based products. Inulin-rich plant materials have promising applications in white biotechnology. This review evaluates the potential of converting inulin through an integrated biorefinery into high-value products by microbial fermentation. It describes the methods for raw biomass and inulin pretreatment, the possibilities of simultaneous saccharification and fermentation (SSF), and the use of wild-type and genetically modified microbial strains. The bioconversion of inulin enables the efficient synthesis of biofuels such as ethanol, butanol, and 2,3-butanediol and biochemicals such as lactic, citric, and poly-γ-glutamic acid. By analyzing the advances in inulin hydrolysis methods, microbial engineering, and bioprocess optimization approaches, this review highlights the broad applicability of inulin in the biorefinery context as a multifunctional, sustainable substrate, which contributes to the development of the circular economy.