Characterization and growth adaptation of Volvariella volvacea cultivated on palm oil empty fruit bunch pellet

Mushrooms are popular valuable foods due to its component that are low in calories, carbohydrates, fat, sodium and cholesterol-free. However, among all edible mushrooms, Volvariella volvacea (paddy straw mushroom) produces low yield and biological efficiency (BE) compared to other edible mushroom species. Moreover, current V. volvacea cultivation technology using palm oil empty fruit bunch (POEFB) stalk as substrate have some limitations and thus reduces the commercialization value for its cultivation. Thus, this research aims to introduce the POEFB pellet as substitutes for POEFB stalk which is smaller in sizes and easier to manage. This study involved 3 research objectives, which are determination of the morphogenesis profiling of V. volvacea mycelium following different substrate and spawn preparation method, optimization of the physiochemical parameters on growth of V. volvacea following different substrate weight, cultivation area, substrate formulation and substrate treatment, and evaluation of the lignocellulolytic degradation during V. volvacea fruiting body induction. Preliminary study using test tube cultivation showed addition of CaCO3 to POEFB increases the growth rates by twofold. Conversely, irradiation of the spawn resulted in no significant changes in growth rates as compared to the control spawn. Optimization of physiochemical parameters showed a large amount of POEFB (6kg) used in a substrate formulation with smaller cultivation area (A1) demonstrated the highest biological efficiency (BE) of V. volvacea. Additionally, POEFB pellet mixed with black soil (F3) is the best formulation for V. volvacea cultivation (generating a BE=17.75%). A pre-autoclaved substrate treatment (ST2) generated the highest BE (14.95%) compared to non-treated substrate and steam treated substrate. Based on the lignocellulolytic enzymes degradation, three enzymes detected which are cellulases, xylanase and laccase. The F3 formulation exhibit the highest lignocellulolytic degradation compared to others. It was observed that lignocellulolytic was highest after 7 days of incubation and resulting in downward pattern when incubation approaching to 35 days mark. In conclusion, POEFB fibre pellet can increase the biological efficiency and suitable to be used as substrate for V. volvacea growth. For future study, it is recommended to further investigate the factors that influence the transition between pinhead into button form in term of its biochemistry and molecular study, as these aspects remain unresolved.