Pretreatment of lignocellulosic biomass for enhanced biogas production.

The aim of this paper is to present a comprehensive review on renewable methane fuel production through the biological route of biomethanation process from major lignocellulosic agricultural crop waste biomass (maize, wheat, rice and sugarcane). Global annual approximate production of major agriculture based lignocellulosic biomass has been explored. Fundamental requirements of biomethanation process have been discussed in details for optimum production of methane. The essential properties of biomass (proximate, ultimate and compositional) conscientious for quality of derived fuel have also been presented along with the pretreatment requirements for lignocellulosic biomass. Methane generation potential of the major lignocellulosic agricultural crop biomass has been explored and presented. Furthermore, the methane production potential and its energetic analysis have also been compared with the bio-ethanol productions. The overall parametric analysis involved in anaerobic digestion and alcoholic fermentation explore that methane generation from lignocellulosic agricultural crop waste biomass is more economical and environmentally beneficial way of biomass utilization in a sustainable way of energy production.

Methane production from lignocellulosic agricultural crop wastes: A review in context to second generation of biofuel production

Protection of environment is of immediate concern and this can only be achieved by avoiding the use of chemicals for fuel production. Lignocellulosic waste is becoming popular as a feedstock for biofuel production. The can be converted into usable form for biofuel production by using a suitable pretreatment method. Different pretreatment methods have been used by researchers which are physical, chemical, physico-chemical, biological and combined pretreatments. Evidently chemical pretreatment is found to be more expensive as a large amount of chemicals are used for pretreating the lignocellulosic substrate. It has been shown that combined pretreatments are more effective as compared to single pretreatment and there is an extensive scope of combinations which can also be applied in future. Recent review critically discusses and compares different pretreatment methods, biomass resources, chemical composition of different agricultural biomass and the use of this biomass for bioenergy generation. Various pretreatment processes used for bio-hydrogen, bio-methane, bio-ethanol, bio-methanol bio-butanol and bio-diesel production are also discussed.

Pretreatment of lignocellulosic wastes for biofuel production: A critical review

Lignocellulosic biomass is an abundant and renewable resource that potentially contains large amounts of energy. It is an interesting alternative for fossil fuels, allowing the production of biofuels and other organic compounds. In this paper, a review devoted to the processing of lignocellulosic materials as substrates for fermentation processes is presented. The review focuses on physical, chemical, physicochemical, enzymatic, and microbiologic methods of biomass pretreatment. In addition to the evaluation of the mentioned methods, the aim of the paper is to understand the possibilities of the biomass pretreatment and their influence on the efficiency of biofuels and organic compounds production. The effects of different pretreatment methods on the lignocellulosic biomass structure are described along with a discussion of the benefits and drawbacks of each method, including the potential generation of inhibitory compounds for enzymatic hydrolysis, the effect on cellulose digestibility, the generation of compounds that are toxic for the environment, and energy and economic demand. The results of the investigations imply that only the stepwise pretreatment procedure may ensure effective fermentation of the lignocellulosic biomass. Pretreatment step is still a challenge for obtaining cost-effective and competitive technology for large-scale conversion of lignocellulosic biomass into fermentable sugars with low inhibitory concentration.

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Pretreatment of Lignocellulosic Materials as Substrates for Fermentation Processes.

Solid-state anaerobic digestion (SS-AD) has gained increasing attention in recent years, especially for digesting lignocellulosic biomass Compared to liquid anaerobic digestion (L-AD), SS-AD handles feedstocks with higher total solids content, and therefore, performs more effectively at higher organic loading rates and has higher volumetric biogas productivity Challenges facing SS-AD of lignocellulosic biomass are primarily related to its relatively low methane yield, potential instability, and low value end-products These challenges are either due to the inherent limits of SS-AD (eg retarded mass transfer caused by high solid content) or can be attributed to the nature of lignocellulosic biomass (eg components recalcitrant to biodegradation) To address these challenges, a variety of methods, including pretreatment of feedstock, improvement of inoculation efficiency, co-digestion of multiple feedstocks, and upgrading biogas to higher-value transportation fuels, have been examined to enhance the performance of SS-AD and increase the value of the end products This review summarizes these challenges in SS-AD of lignocellulosic biomass and discusses the mechanisms and feasibility of potential strategies for resolving them

H. Takeuchi

Papers

Hydrothermal pretreatment of rice straw biomass: A potential and promising method for enhanced methane production