Bioprocess Modelling on Lignocellulosic Biomass

Sushantika Deviyani^*
*Correspondence: Sushantika Deviyani, Department of Biotechnology, University of Colombo, Colombo, Sri Lanka, Email:

Description

Lignocellulosic feedstocks, which are currently unused, can be used to produce biofuels like as ethanol, as well as bio-refinery applications. Despite the fact that lignocellulose bioconversion via microbial or yeast fermentation has been documented, designing an efficient and cost-effective lignocellulosic fermentation process remains a challenge due to the numerous process factors involved in bioprocess design, optimization, and scale-up. In high-production mechanisms, bioprocess modelling approaches have been demonstrated to be useful in obtaining high yield, productivity, or dilution of specific product efficiency. Several forms of lignocellulosic bioprocess modelling have been developed and successfully validated as a viable option for designing, optimizing, and scaling up biomass-based operations. This subject gives an overview of various modelling techniques and how they may be utilized to create efficient and cost-effective lignocellulose-based bioprocesses.

As fermentation feedstock for bio-based products, low-cost, accessible, and renewable lignocellulosic biomass has emerged as a potential alternative to corn and starch. These substrates can be made from agricultural, industrial, and municipal solid wastes, as well as forestry leftovers. The use of lignocellulose resources to make bio-chemicals and biofuels is regarded to be both cost-effective and ecologically benign. Several biotech companies and pilot plants in Europe and the United States are quickly optimizing and scaling up lignocellulosic bioprocess technologies. Degradation of lignocellulosic biomass to provide monomeric sugars for fermentation is required for lignocellulose bioconversion to bio-products. The most typical method of lignocellulose hydrolysis is pretreatment with heat and/or chemical agents, followed by enzyme hydrolysis. Many studies have demonstrated that lignocellulosic feedstock may be exploited by bacteria (e.g. Zymomonas mobilis, Escherichia coli) and yeasts (e.g., Saccharomyces cerevisiae and Scheffersomyces stipitis) to make bio-products.

Lignocellulosic bioprocesses, namely cell modelling employing kinetics,stoichiometry, and integrative techniques, as well as fermentation kinetic modelling used for process performance evaluations.

One of the problems of lignocellulose fermentation is the presence of a sugar molecule (mainly glucose and xylose) produced during the pre-treatment and enzyme hydrolysis of lignocellulosic materials. From an economic standpoint, these sugars must be effectively fermented by microbes into the needed output. The fluctuation of sugar composition in different biomass feedstocks, 30% - 50% and 10% - 25% of dry weight for glucose and xylose respectively, has a significant impact on fermentation performance because an organism may be unable to adjust its fermentation capacity optimally to match the change in sugar composition, resulting in a long fermentation time. A culture system that can survive variations in sugar composition and successfully ferment the sugar combination is required to fulfil the technical and economic requirements of an industrial lignocellulose-based process.

Another difficulty with lignocellulosic fermentation is the existence of inhibitory chemicals (such as acetic acid and furans) created during pretreatment, which effectively limit the growth and efficacy of the fermenting organism. These inhibitors present significant barriers to the widespread implementation of lignocellulose-based bioprocesses. The necessity for removing inhibitors via physical and chemical approaches is significant,resulting in a loss off. In order to improve process efficiency, inhibitor-tolerant microorganisms should be included in the fermentation, or optimised process architecture can be used to prevent inhibitory effects.

The development of an inhibitor-tolerant cell factory includes investigating the mechanisms of known inhibitors as well as metabolic and evolutionary engineering approaches for creating threshold strains. As a result, this concentrates on fermentation process configuration in order to solve inhibitor and fermentative end product inhibition difficulties. Furthermore, problems with lignocellulosic biomass viscosity and partial insolubility may result in poor mixing and restricted mass and heat transmission, particularly when the fermentation process is carried out at a high solids level. A fed-batch process setup with correct mixing must be created to increase process efficiency.

Conflict of Interest

Author has nothing to disclose.