Alternative supplements for Agaricus bisporus production and the response on lignocellulolytic enzymes

Abstract

Four experimental supplements were prepared for the production of Agaricus bisporus comprising compost with corn bran (CCB), a mixture of corn bran with corn gluten (CCBCG), corn bran with vegetal oil (CCBVO), and corn bran with corn gluten and vegetal oil (CCBCGVO). The mixtures were designed to obtain the final composition of a cracked soybean (CS) supplement consisting of 25% protein and 18% oil. The supplements were added at 3.3% (w/w) to compost at spawning. We used two control groups: compost without supplement (UC) and compost with CS. Production was measured in three flushes; the CS supplements in the CCBCGVO mixture reached a cumulative production above 34kg/m2 (P<0.05). Samples were taken in the compost at spawning (Day 0), primordia formation (25 d), and at the end of the first, second, and third breaks (39, 48, and 60 d, respectively); enzymatic activities (cellulase, xylanase, and laccase) were also determined. For cellulase and xylanse activities, a positive correlation was found between production values and the increase in these enzymes, in presence of supplements. The maximum value in laccase activity was at 25 d (beginning of primordia formation), activity decreased in the production stages, and it increased again at day 60 (end of the third stage). In this study, a novel supplement was formulated based on corn bran, gluten, and vegetal oil, achieving mushroom yields similar to those obtained with a CS.