PRODUCTION OF HYDROLYTIC ENZYMES BY SOLID-STATE FERMENTATION WITH NEW FUNGAL STRAINS USING ORANGE BY-PRODUCTS

Orange is the most-produced citrus fruit worldwide, and its residues, which are discarded, represent 50% of the fruit. These residues cause major contamination problems. Orange peels are rich in cellulose, hemicellulose and pectin, which can be used for the production of enzymes. In this study, oranges-colonizing fungi Were isolated and identified by 5.8S rRNA-ITS ribosomal sequence analysis as Fusarium sp. N6C6, Cladosporium oxysportum N1C1, Mucor racemosus N9C1. and Penicillium minioluteum N3C2. These strains and Trichoderma reesei ATCC 26921 were used for the production of endoglucanases (EG), xylanases (XYL) and polygalacturonases (PGA) by solid-state fermentation rising orange peels. P. mintoluteum N3C2 obtained 6.5 U/g of dry peel (DP), the highest production of EG, surpassing Trichoderma reesei ATCC 26921 (3.3 U/g DP) T. reesei ATCC 26921 and P. minioluteum N3C2 obtained the highest production of XYL, at 14.7 and 14.5 U/g DP; respectively. The highest PGA production was obtained with Fusarium sp. N6C6 (16.5 U/g DP), followed by M. racemosus N9C1 (12.3 U/g DP), which produced less EG. C. oxysporum N1C1 produced EG (3.2 U/g DP) and PGA (8.0 U/g DP) but did not produce XYL. The strains studied possess great potential for the production of enzymes that could be used in the extraction of citric oils.