Supplementation of watermelon peels as an enhancer of lipase and esterase production by Yarrowia lipolytica in solid-state fermentation and their potential use as biocatalysts in poly(ethylene terephthalate) (PET) depolymerization reactions.

Yarrowia lipolytica is a yeast that presents high biotechnological potential due to its ability to produce many metabolites, among them lipases and esterases, which are important industrial biocatalysts. Since Brazil is an agroindustrial country, it generates an enormous diversity of residues or byproducts that can be used as a platform for biomolecules production. This work aims to evaluate lipase and esterase production by Y. lipolytica via solid-state fermentation using soybean bran and soybean bran supplemented with watermelon peels in different contents, and subsequent use of the enzyme extracts for poly(ethylene terephthalate) (PET) hydrolysis. Supplementation of watermelon peels in the lowest content led to an improvement of lipase activity in almost 31%, reaching 75.22 U g−1. Esterase productivity was 1.5-fold higher when 20 wt% of watermelon peels were added to the media culture. Timecourse evaluation of enzymes production showed a maximum lipase activity in 14 h and similar esterase activity in 14 and 20 h of fermentation. Proteases production were also intensified in supplemented samples. Enzymes produced with 5 wt% watermelon peels supplementation led to higher terephthalic acid concentration (up to 42.02 µmol L−1) during PET depolymerization. Results suggest a great potential of enzyme production in low cost fermentative media to act as biocatalysts in PET hydrolysis reactions. [ABSTRACT FROM AUTHOR]