Unlocking Kluyveromyces marxianus for efficient protein expression and single-cell protein production

The non-conventional yeast Kluyveromyces marxianus is emerging as a versatile food-grade host with exceptional potential in industrial biotechnology, due to its rapid growth, thermotolerance, and metabolic flexibility. Its broad substrate utilization capacity and GRAS status have spurred growing interest in its application for recombinant protein expression and single-cell protein (SCP) production. However, a comprehensive understanding of the functional genomics and metabolic networks in K. marxianus remains limited. Nevertheless, ongoing efforts to develop diverse genetic engineering tools for K. marxianus have greatly strengthened its potential as a promising platform. In this review, we provide an extensive overview of the genetic, physiological, and biotechnological characteristics that establishes K. marxianus as an ideal host for efficient protein expression and SCP production. Recent advances and representative examples of engineering strategies aimed at unlocking its industrial potential for bioproduction were discussed. Finally, this review highlights the challenges and future directions for biotechnological innovations.