Biotransformation of Sugar-Containing Wastewater into a-1,3-Glucan Based Bioplastic

Biotechnology | Research article | https://doi.org/10.47262/SL/13.1.132024370

Biotransformation of Sugar-Containing Wastewater into α-1,3-Glucan Based Bioplastic

Yao Chang, Yang Wang*

Department of Biochemistry, School of Environmental and Bioengineering, Nanjing University of Science and Technology, 200-Xiaolingwei, Nanjing, Jiangsu, China

Abstract

With the advent of synthetic biology, wastewater is turning into a resource, especially from sugar industry wastewater, which is rich in organic matter. Efficient transformation and purification of synthetic products are the bottleneck for the recycling and reuse of wastewater. To address this issue, here we extracted a gene expressing glucosyltransferase from Streptococcus salivarius and engineered it into the bacterium Bacillus subtilis for the secretion of glucosyltransferase to transform sucrose in the wastewater into α-1,3-glucan which is prone to precipitate, thus facilitating purification. The α-1,3-glucan polysaccharide harvested from wastewater was then turned into bioplastic film through oxidative double crosslinking, which showed a synergistic effect on the mechanical strength of bioplastic film. Compared to common bioplastic and chemically crosslinked bioplastic, the stress-strain curves, tensile strength and Young's modulus were significantly higher in double crosslinked bioplastics. In addition, thermal decomposition rate of the double crosslinked bioplastic was found lower than the other two bioplastic materials. As a proof of concept, this strategy paved the way for water recycling and eco-friendly material production.