Recent advances in the life cycle assessment of biodiesel production linked to azo dye degradation using yeast symbionts of termite guts: A critical review

Abstract

Beyond energy crisis, biodiesel offers renewable and unlimited option to the challenges associated with fossil fuels depletion. Biodiesel could reduce the carbon foot print and gas emissions. Therefore, China has set an audacious goal of carbon neutrality by 2060. In order to reduce the cost of biodiesel production, it is critical to look for alternative feedstocks and unconventional resources. Biodiesel can be produced from renewable and sustainable feedstocks like edible and non-edible oils, insects, municipal sewage sludge, and oleaginous microorganisms. Existing life cycle assessments of yeast-based biodiesel production are required to assess potential environmental impacts and obtain a holistic picture. The circular economy paradigm has recently emerged as a viable alternative to linear, unsustainable production and consumption systems. Given the legislative requirements and the circular economy principle, the use of textile azo dye wastewater is a promising alternative for its management. The annual disposal of 4,500,000 tons of textile dyes is an environmental and socioeconomic concern due to their carcinogenic potential. Azo dyes account for over 70% of global industrial demand. Biological-mediated azo dye degradation is thought to be cost-effective, and environmentally friendly when compared to physical and chemical approaches. To this end, yeasts can play a significant role, owing to their high growth rate, tolerance to extreme conditions, and ability to effectively degrade lignin and aromatic compounds, concurrently representing a highly promising feedstock for biodiesel production. Interestingly, an emphasis has been recently given on novel symbiotic yeasts isolated from termite guts as promising microbiomes for multiple biotechnological applications. Therefore, this review focuses on recent findings of biodiesel production from azo dye degrading yeasts inhabiting termite guts. While capturing recent research advancements for sustainable biodiesel production, this review emphasizes a novel concept for using azo dyes/aromatic wastes as a feedstock for biodiesel production.