Sustainable Utilization of Catla catla Scales: Formulation and Production of Microbial Nutrient Media

The fish processing sector presents environmental challenges due to the generation of by-products like viscera, scales, fins, frames and gills. This study focuses on sustainably utilizing scales from Catla catla, a by-product of this industry, by converting them into nutrient-rich media for microbial culture via acid hydrolysis. The aim is to formulate to develop and to validate a comprehensive microbial nutrient medium sourced from freshwater fish scales. The process involves acid hydrolysis of Catla catla scales at 37°C for 15-17 hours, utilizing 10% hydrochloric acid, followed by heating at 100°C for 2-3 hours and subsequent neutralization with 1N sodium hydroxide. The properties of the resulting hydrolysate powder were analyzed for compositional amounts of total nitrogen, ash, fat and moisture content, solubility and ability to support the growth and multiplication of bacterial strains Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The findings revealed that the microbial medium derived from Catla catla scales exhibited a chemical composition of 4.5% moisture, 16.33% total nitrogen, 0.31% fat and 6.5% ash, with a pH of 7.1 and a solubility of 99.25%. In bacterial growth tests, the medium produced from Catla catla scales demonstrated a faster growth rate compared to commercial media. These results suggest that Catla catla scales, as a by-product, hold promise as a raw material for producing a complete nutrient microbial medium, serving as an efficient growth medium for bacteria. This approach contributes significantly to both environmental sustainability and resource optimization within the fish processing industry.