Fuente: PubMed "microbial biotechnology" iScience. 2026 Apr 20;29(5):115755. doi: 10.1016/j.isci.2026.115755. eCollection 2026 May 15.ABSTRACTKeratin is one of the most recalcitrant biopolymers due to its dense disulfide crosslinks; yet, how microbial keratin degradation is regulated under nutrient limitation remains poorly understood. Here, we integrated time-resolved transcriptomics, proteomics, and metabolomics to investigate starvation-driven keratin utilization in the extremophilic bacterium Fervidobacterium islandicum AW-1. Although keratinolytic proteases are constitutively expressed, starvation induces a coordinated regulatory program that couples keratin degradation to stress adaptation. Under nutrient limitation, cells degraded keratin through localized membrane-associated proteases, while redox-mediated sulfitolysis and Fe-S cluster biogenesis facilitated disulfide bond cleavage and redox balance. Metabolic rewiring favored the Entner-Doudoroff pathway and the reverse TCA cycle, conserving energy under oligotrophic conditions. Starvation further activated the stringent response and cyclic-di-GMP-associated signaling, promoting biofilm formation, persistence-like behavior, and substrate colonization. Together, these findings propose a systems-level model linking keratin degradation to regulatory and metabolic networks that support microbial persistence in extreme environments and keratin waste valorization.PMID:42111188 | PMC:PMC13157175 | DOI:10.1016/j.isci.2026.115755