Intensification of violacein production from agro-industrial by-products using solid-state fermentation by Janthinobacterium lividum

Abstract

The accumulation of agro-industrial residues is a major environmental and economic challenge, encouraging sustainable bioprocesses for their conversion into high-value products. Solid-state fermentation (SSF) is a promising strategy due to low water use, reduced energy demand, and high substrate compatibility. In this context, violacein, a bisindole-derived purple pigment produced by several bacterial species, has gained interest because of its broad biological activities, including antimicrobial, antitumor, and immunomodulatory effects. However, its industrial application remains limited by low production yields under conventional submerged fermentation conditions. Aim of the study: This study aimed to evaluate the potential of diverse agro-industrial by-products as low-cost substrates for violacein production by Janthinobacterium lividum under SSF conditions, and to optimize key process parameters to maximize production efficiency.