Improvement of Large-Scale Production of Lignocellulosic Bioethanol through Synthetic Biology Approaches: A Comprehensive Review

Souvik Roy 1, *, Sampreet Manna 1, Subhayu Chowdhury 1 and Lopamudra Choudhury 2

1 Post-Graduate & Research Department of Biotechnology, St. Xavier’s College (Autonomous), 30, Mother Teresa Sarani, Kolkata-700 016, West Bengal, India.
2 Department of Microbiology, Sarsuna College (under Calcutta University), 4/HB/A, Ho-Chi-Minh Sarani, Sarsuna Upanagari, Kolkata – 700 061, West Bengal, India.
 
Review
World Journal of Biology Pharmacy and Health Sciences, 2023, 14(03), 316–331.
Article DOI: 10.30574/wjbphs.2023.14.3.0275
Publication history: 
Received on 09 May 2023; revised on 22 June 2023; accepted on 24 June 2023
 
Abstract: 
This review article explores the use of synthetic biology approaches like gene editing and metabolic engineering to create genetically-modified organisms that can produce commercially-valuable products on large-scale, clean environmental pollutants, and serve as efficient biosensors. The Biobrick system includes a registry of available genetic information and a set of standard protocols for assembling and testing them, which finds various significant uses in synthetic biology, such as in the production of "Fourth generation” biofuel. Genetic engineering techniques may be applied to manipulate crops or microbes for more efficient biofuel production. Such synthetic biology techniques also include modification of lignin structure and content, use of bacterial enzymes abundantly expressed in plants, and manipulation of hemicellulose biosynthesis. However, challenges such as high temperature, efficient conversion of all substrate molecules for maximum product yield, efficient pentose fermentation, and tolerance to acetic acid and bioethanol concentration can all impact the yield of the product. This article explores innovative genetic modification approaches designed to decrease lignin levels and enhance crop digestibility in plants, with a specific focus on the model plant Arabidopsis thaliana and herbaceous plants such as Alfalfa. The aim is to manipulate the Monolignol pathway and modify the CSE gene, known for its ability to decrease lignin content. These modifications have been shown to significantly improve saccharification efficiency and increase the yield of lignocellulosic bioethanol. Besides, the role of xylulose-5-phosphate as an intermediate in the non-oxidative pentose phosphate pathway and the oxidative pentose phosphate pathway, and the use of heterologous xylose transporters and modified sugar transporters as potential solutions to improve the biofuel production efficiency is also discussed in this review article. 
 
Keywords: 
"Fourth Generation” Biofuel; Gene Editing; Genetically-Modified Organisms; Lignocellulosic Bioethanol; Metabolic Engineering; Synthetic Biology
 
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