Valorization of Pectin-rich Agroindustrial Wastes by Fermentation

Abstract

The search of the biotechnological ways to the integral use of the wastes generated by the coffee and citric agroindustries, is a current problem. The biotransformation of coffee pulp and orange mesocarp during aerobic and anoxic fermentation with the pectinolític yeast Kluyveromyces marxianus CCEBI 2011 was studied in this research. It was found that coffee pulp is a better substrate to yeast growth, which was evidenced throughout a better conversion of the carbon and energy source. The yeast used in 24 h the reducing and neutral sugars from substrates efficiently, either under aerobic or oxygen-limited cultures. The excretion of the polygalacturonase enzyme by the yeast lead to the increasing in the pectic substances extraction, which reached the 225 % and 33 % for coffee pulp and orange mesocarp, respectively, compared with the amounts which were extracted during substrates sterilization. The enzyme production by the microorganism presented not significantly differences in relation to the substrate used, but the contrary occurred with respect to glucose concentration in the medium. These results point to the promissory use of the K. marxianus CCEBI 2011 yeast strain in the valorization of pectin-rich agricultural wastes by means of their conversion in potential plant elicitors and prebiotics oligogalacturonides-based.