A sequential design strategy was applied to optimize the secretion of pectinases by a Saccharomyces cerevisiae strain, from Brazilian sugarcane liquor vat, on passion fruit residue flour (PFRF), through solid-state fermentation (SSF). A factorial design was performed to determine the influence variables and two rotational central composite designs were executed. The validated experimental result was of 7.1 U mL−1 using 50% PFRF (w/w), pH 5, 30 °C for 24 h, under static SSF. Polygalacturonase, pectin methyl esterase, pectin–lyase and pectate–lyase activities were 3.5; 0.08; 3.1 and 0.8 U mL−1, respectively. Shotgun proteomics analysis of the crude extract enabled the identification of two pectin–lyases, one pectate–lyase and a glucosidase. The crude enzymatic extract maintained at least 80% of its original activity at pH values and temperatures ranging from 2 to 8 and 30 to 80 °C, respectively, over 60 min incubation. Results revealed that PFRF might be a cost-effective and eco-friendly substrate to produce pectinases. Statistical optimization led to fermentation conditions wherein pectin active proteins predominated. To the extent of our knowledge, this is the first study reporting the synthesis of pectate lyase by S. cerevisiae.

Yeasts play a fundamental role in nature, and due to their biochemical and physiological versatility, many of them can have their metabolic routes regulated and optimized for the biosynthesis of specific products. In view of this potentiality, new contributions that dedicate to the study of fermentative processes involving yeasts as protagonists, especially for the production of value-added products from lost vegetables and their residues, show importance. Among these products, particularly in this brief review, the production of pectinase and yeast probiotic potential in alternative culture media is mentioned as a way to make these processes more economically and environmentally viable.

Effects of heat pretreatment on the yield and bioactivity of powdered egg whites hydrolysates by three different proteases. Efeito do pré-tratamento térmico sobre o rendimento e a bioatividade de hidrolisados de clara de ovo em pó por três diferentes proteases.

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