Plastic bio-mitigation by Pseudomonas mendocina ABF786 and simultaneous conversion of its CO2 byproduct to microalgal biodiesel

Abstract

Bio-mitigation of plastics by microorganisms generates carbon dioxide (CO₂) that can be utilized for algal biomass generation. Pseudomonas mendocina ABF786, reportedly the most efficient plastic-degrading bacteria, was screened using the modified most probable number technique. This study highlights the use of an integrative prototype for the production of microalgal biomass (Chlorella vulgaris) in combination with bio-mitigation of plastics, which serves a dual purpose: (i) increased plastic-degradation capability by microorganisms (53%-85% increase in plastic weight loss) due to removal of CO₂ feedback inhibition and (ii) increased algal biomass generation (200%-237%) due to supply of extra CO₂ from plastic degradation to the algal cultivation flask. Whole-genome sequencing and functional annotation confirmed that all the genes involved in the mineralization of plastic to CO₂ are present within the genome of P. mendocina ABF786. Using two or more microbial cultures for remediation may increase the process efficiency.

Keywords: Bioremediation; Chlorella vulgaris; Marine bacteria; Modified most probable number; Transesterification.