Biological Pretreatment by Solid-State Fermentation of Oat Straw to Enhance Physical Quality of Pellets

Wei Gao,Lope G Tabil,Rongfei Zhao,Zhiqiang Lei

doi:10.1155/2020/3060475

Wei Gao, Lope G Tabil + Show 2 more

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https://doi.org/10.1155/2020/3060475

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Abstract

Pelleting can increase the efficiency of handling and transportation of biomass. Pretreatment obtains lignin fragments by disrupting the lignocellulosic structure of biomass and ensures the high-quality compressed pellets. In this study, solid-state fermentation (SSF) is used as a biological method to improve the quality of pellets of oat straw. SSF of oat straw using Trametes versicolor 52J (TV52J) and Phanerochaete chrysosporium (PC) was conducted. Response surface methodology (RSM) was employed by using a four-factor, three-level Box–Behnken design with fermentation time (days), moisture content (%), particle size (mm), and fermentation temperature (°C) as independent parameters. Pellet density, dimensional stability, and tensile strength were the response variables. The optimization options of fermentation time (33.96 and 35 days), moisture content (70%), particle size (150 and 50 mm), and fermentation temperature (22°C) of oat straw pretreated with these two fungal strains were obtained. The microscopic structural changes of oat straw caused by biological pretreatment were investigated by scanning electron microscopy (SEM). Observation results of SEM showed that the connection between single fibers became relatively loose, and this was beneficial to improve the physical quality of the pellets.

Highlights

With the depletion of fossil fuel resources and the emission of greenhouse gases, it is urgent to find alternative energy sources to ensure the access and safety of energy [1,2,3,4]
Results and Discussion e experimental results are shown in Table 2. e average tensile strength of pellets made from oat straw pretreated with Trametes versicolor 52J (TV52J) and Phanerochaete chrysosporium (PC) varied from 0.169 to 0.362 MPa and 0.147 to 0.279 MPa, respectively
The analysis of variance (ANOVA) of density 0, density 1, dimensional stability, and tensile strength influenced by fermentation time, moisture content, particle size, and fermentation temperature is summarized in Tables 3 and 4

Summary

Introduction

With the depletion of fossil fuel resources and the emission of greenhouse gases, it is urgent to find alternative energy sources to ensure the access and safety of energy [1,2,3,4]. Lignocellulosic biomass straw has the advantages of rich resources and low cost, which is considered as an important resource of biofuel production. Cereal straw is the largest biomass raw material, with an annual global output of about 1.5 Gt [5, 6]. Due to the irregular shape and low bulk density of dry state of cereal straw, it is difficult to handle, transport, and use as fuel. Bulk density of dry barley straw is approximately 40 kg/m3 [7, 8]. Is leads to high transportation and storage costs, accounting for more than 35% of biofuel production expenditures [9, 10]. The energy content of biomass in dry state is about half of the coal, which is 16–20 MJ/kg [7]

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Results

Conclusion