Valorisation of effluents obtained from chemical and enzymatic chitin production of Illex argentinus pen by-products as nutrient supplements for various bacterial fermentations

The industrial production of chitin generates large volumes of protein effluents that need to be handled and depurated before discharge. The current study highlights the suitability of four effluents, derived from the chemical and enzymatic hydrolysis of Illex argentinus pen to produce β-chitin, as peptones for the growth and metabolite production of six bacteria with different nutrient requirements. Batch cultures were carried out determining the growths by dry weight and viable cell counts and modelling kinetics using the logistic equation. Two lactic acid bacteria were perfectly supported by alternative media formulated with chitin effluents and the results were better than those found in commercial ones. For the other four bacteria, the biomasses in chitin peptones were lower but the number of produced cells was similar to those defined using Marine medium (MM) and tryptone-soy broth (TSB). An economic assessment demonstrated the profitability achieved when commercial peptones are replaced by those generated from squid pen: reduction of costs by 6 times for lactic acid bacteria, 50-100 times for marine bacteria and 6-17 times for Gram (+) bacteria.