Development of a consortium-based microbial agent beneficial to composting of distilled grain waste for Pleurotus ostreatus cultivation

Zemin Fang,Sibao Wu,Guopai Xie,Yong Fang,Yuting Ma,Xuezhi Gao,Rongrong Zhou,Juanjuan Liu,Yazhong Xiao

doi:10.1186/s13068-021-02089-4

Zemin Fang, Sibao Wu + Show 7 more

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https://doi.org/10.1186/s13068-021-02089-4

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Abstract

BackgroundPleurotus ostreatus is an edible mushroom popularly cultivated worldwide. Distilled grain waste (DGW) is a potential substrate for P. ostreatus cultivation. However, components in DGW restrict P. ostreatus mycelial growth. Therefore, a cost-effective approach to facilitate rapid P. ostreatus colonization on DGW substrate will benefit P. ostreatus cultivation and DGW recycling.ResultsFive dominant indigenous bacteria, Sphingobacterium sp. X1, Ureibacillus sp. X2, Pseudoxanthomonas sp. X3, Geobacillus sp. X4, and Aeribacillus sp. X5, were isolated from DGW and selected to develop a consortium-based microbial agent to compost DGW for P. ostreatus cultivation. Microbial agent inoculation led to faster carbohydrate metabolism, a higher temperature (73.2 vs. 71.2 °C), a longer thermophilic phase (5 vs. 3 days), and significant dynamic changes in microbial community composition and diversity in composts than those of the controls. Metagenomic analysis showed the enhanced microbial metabolisms, such as xenobiotic biodegradation and metabolism and terpenoid and polyketide metabolism, during the mesophilic phase after microbial agent inoculation, which may facilitate the fungal colonization on the substrate. In accordance with the bioinformatic analysis, a faster colonization of P. ostreatus was observed in the composts with microbial inoculation than in control after composting for 48 h, as indicated from substantially higher fungal ergosterol content, faster lignocellulose degradation, and higher lignocellulase activities in the former than in the latter. The final mushroom yield shared no significant difference between composts with microbial inoculation and control, with 0.67 ± 0.05 and 0.60 ± 0.04 kg fresh mushroom/kg DGW, respectively (p > 0.05).ConclusionThe consortium-based microbial agent comprised indigenous microorganisms showing application potential in composting DGW for providing substrate for P. ostreatus cultivation and will provide an alternative to facilitate DGW recycling.

Highlights

Pleurotus ostreatus is an edible mushroom popularly cultivated worldwide
Screening bacteria from distilled grain waste compost for microbial inoculation In order to obtain indigenous microorganisms to develop a microbial agent for Distilled grain waste (DGW) composting, samples from the thermophilic phase of DGW composting were used as the source of beneficial bacteria [15]
Results revealed that Thermobacillus, Thermoactinomyces, Stenotrophomonas, Pseudomonas, Symbiobacterium, Pseudoxanthomonas, Ureibacillus, Caldibacillus, Sphingobacterium, Thermobifida, Aeribacillus, Bacillus, Geobacillus, Chelatococcus, and Thermovum were the top 15 genera in the thermophilic phase of DGW compost (Fig. 1a)

Summary

Introduction

Pleurotus ostreatus is an edible mushroom popularly cultivated worldwide. Commonly known as the oyster mushroom, is cultivated worldwide and has become the second most popularly cultivated edible mushroom during the last 10 years [1]. P. ostreatus requires a shorter growth time when compared to other edible mushrooms and grows on a broad range of natural substrates from woodland, agricultural, and animal husbandry [1, 3]. Various agricultural and agro-industrial by-products, such as straw, grass, sawdust, coffee pulp, and corncob are suitable substrates for P. ostreatus cultivation. Materials from local places are recommended for cultivators from different countries to lower the costs of cultivation substrates. In Asian countries, sorghum, coffee pulp, cottonseed hulls, and wheat straw are popular materials used in P. ostreatus cultivation [1]

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