Exploring oyster mushroom (Pleurotus ostreatus) substrate preparation by varying phase I composting time: changes in bacterial communities and physicochemical composition of biomass impacting mushroom yields.

AIMS: To investigate characterization of the bacterial community composition and functionality and their impact on substrate biodegradation as well as mushroom yield. METHODS AND RESULTS: Bacterial diversity, composition and functionality were accessed by DNA-derived analysis for a sugarcane straw-based substrate composted for either 5, 10 or 15 days. In addition, carbon and nitrogen losses, carbohydrate conversion and mushroom yields were measured for the different treatments. Changes were observed in the bacterial community diversity and composition after the process started, but not during the composting process itself. Following phase I, Acinetobacter sequences were recovered in high numbers, and selected genes associated with nitrogen metabolism and lignocellulose deconstruction were mapped. Substrate physicochemical composition showed elevated carbon and nitrogen losses after 10 and 15 days of phase I with reductions in mushroom yield. CONCLUSIONS: Acinetobacter species appear to play an important role in substrate degradation processes, and a 5-day phase I period showed a significant higher mushroom yield compared to composting for either 10 or 15 days. SIGNIFICANCE AND IMPACT OF THE STUDY: This study confers a better understanding of the bacterial community manipulation during the substrate preparation and their influence in substrate selectivity for the Pleurotus ostreatus cultivation.

Selection of strains for shiitake production in axenic substrate.

Shiitake mushroom consumption is increasing in Brazil. In addition to the implementation of new production methods, it is also important to increase productivity, quality and reduce production costs. In this study, six commercial Lentinula edodes strains were characterized for genetic diversity (rep-PCR analysis) and mushroom production (yield, number and weight of individual mushrooms) using different substrates and cultural conditions. All strains showed genetic differences by repetitive element palindromic based-polymerase chain reaction (rep-PCR). The richest substrate resulted in the greatest production under both environmental conditions. Strains LE4 and LE6 produced the majority of their mushrooms earlier than the other strains. The highest number of mushrooms was observed in the LE6 strain while the highest weights of individual mushrooms were observed in the LE4 strain. Controlled environmental conditions resulted in superior production for all strains, except for LE4, which had empirically greater yield in the semi-controlled environmental condition.