Is Xylose the Future of Biofuels?
With the increasing deterioration of our environment and cultural focus on sustainability, seeking a favorable replacement for traditional, non-renewable fossil fuels is of the utmost importance. One of the alternatives garnering a lot of attention is lignocellulosic biomass. It's part of an environmental-friendly replacement for fossil fuels and manufacturing chemicals. Biomass is one of the most abundant resources available today and can be derived from many plants, crops (such as sugar cane), or other organic farm waste. Using biomass to create biofuel is cost-effective, sustainable, and easily produced at large scales makes it a viable source for biofuel creation.
To use biomass for biofuel creation, scientists have been testing many different processes for viability. Procured from hemicellulose, xylose is the second most common sugar found in nature. It accounts for 18-30% of lignocellulose hydrolysate sugars. Xylose is widely understood to be one of best feedstocks for creating biofuels.
Eliminate metabolic restriction to enhance the xylose efficiency
Multiple plans of action have been attempted for the improvement of xylose utilization in biofuels. The absence of xylose-specific transporters in yeast accentuates the need for efficient xylose utilization. Determining high-attraction xylose transporters can remarkably enhance xylose utilization rates and increase glucose content in yeast from Meyerozyma guilliermondii scheffersomyces stipitis, and Gxs1 from candida intermedia.
Biofuel production through adjusting metabolic pathway
Bioethanol gathered a lot of attention during biofuel production from biomass. During the initial phase of the production, various metabolic engineering methods were applied to refine and enhance the process of creating ethanol from xylose. A lot of remarkable progress was observed during this phase of ethanol production.
Building efficient xylose-fermenting Saccharomyces cerevisiae
Using engineered saccharomyces cerevisiae, ethanol was derived from xylose. The xylose metabolic genes (XYL1, XYL2, and XYL3) found in Scheffersomyces stipitis were used by introducing them into S. cerevisiae to get the engineered version of this specie of yeast. However, this process manifests unwanted phenotypes like slow xylose absorption and xylitol accumulation. The initial reason for this was to create a better xylose-fermenting strain through the development of a synthetic isozyme system of xylose reductase (XR).
Is xylose the future of biofuels?
Xylose is an amazing resource for creating biofuels. Many of the large fuel companies are working on ways to patent and use xylose in their biofuel processes.
Since microorganisms like S. cerevisiae cannot metabolize xylose organically, artificial paths were modernized by recognizing heterologous xylose transporter and catabolic genes. Biofuel is created from xylose through the reassimilation of microorganisms. Metabolic engineering was utilized to improve the production process.
The main challenge faced today in creating biofuel from xylose is the high cost of xylose in the market, which translates to high production costs. Many companies in the US and overseas are focused on affordable ways of producing xylose from sugarcane, hemp biomass, or trash. Because of this focus, xylose will have a significant future in the biofuel industry.
Additional Sources:
https://www.energy.gov/eere/bioenergy/biofuel-basics
https://www.sciencedirect.com/science/article/abs/pii/S0958166918300892