Wheat Straw Optimization via its Efficient Pretreatment for Improved Biogas Production

Muhammad Jaffar Memon,Abdul Rehman Memon

doi:10.28991/cej-2020-03091528

Muhammad Jaffar Memon, Abdul Rehman Memon

Open Access

https://doi.org/10.28991/cej-2020-03091528

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Abstract

The complex indigenous configuration of non-bio-labile wheat straw necessitates its pretreatment to optimize the breakdown of its structural components for its ultimate conversion into biogas by means of anaerobic digestion. In this research work, wheat straw was pretreated with potassium hydroxide (KOH) to facilitate its improved biodegradability. The pretreatment of wheat straw was also obvious in terms of its crystallinity resulting in the improved amorphous regions compared to the control wheat straw. The results showed that pretreated wheat straw digestion transpired into comparatively higher removal of TS (86%), VS (89%) and total lignin, cellulose and hemicellulose (22%) than that obtained with control wheat straw. Maximum biogas production accrued was 1550 mLN per day with optimized dosing of KOH compared to 967 mLN per day obtained with control wheat straw, implying that the cumulative biogas production was improved by 45% using pretreated wheat straw than that using control wheat straw. These results suggested that pretreated wheat straw digestion led to a significant improvement in the biogas yield.

Highlights

Harnessing biogas energy could be one of the most important options to undertake to realize one of the goals of clean energy as outlined under the banner of united nation’s sustainable development goals [1]
The pretreatment results suggested that alkali treatment of wheat straw induced breakdown of lignocelluloses comprising of three main polymeric constituents Lignin, cellulose and hemicellulose (LHC) in terms of their reduced concentration levels as reflected via the altered physical characteristics of treated wheat straw [17]
The induced changes in wheat straw characteristics are directly proportional to its efficient biodegradability under the influence of its anaerobic digestion leading to enhanced biogas production [18]

Summary

Introduction

Harnessing biogas energy could be one of the most important options to undertake to realize one of the goals of clean energy as outlined under the banner of united nation’s sustainable development goals [1]. Wheat straw is one of the potential low-cost lignocellulosic biomass used as a key substrate in bio-refineries and for biogas production [2]. The level of recalcitrance of the LHC needs to be compromised so as to overcome the limitations that are expected per se during the course of enzymatic and microbial degradation of wheat straw [3]. To address this complexity, wheat straw pretreatment is required beforehand to make the LHC compliant to an extent so that it results in its optimum biodegradability during the course of its digestion. Alkaline pretreatment leads to an increase in the accessible surface area and porosity of the straw, as well as decreases the cellulose crystallinity and induces disruption in the lignin structure [8]

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