Valorization of cashew industry wastewater as a carbon and nutrient source for the microbial growth and production of the polyhydroxyalkanoates: A potential biopolymer by Bacillus species

Abstract Wide applications of conventional plastics across the world have made its production inevitable. To avoid the ecocide occurring due to conventional plastics, studies on the production and extraction of renowned biopolymers like polyhydroxyalkanoates (PHAs) are explored. PHA is a family of polyesters naturally produced by bacterial fermentation with the potential to replace conventional hydrocarbon-based polymers. The efficient utilization of industrial discard as renewable feedstocks in the production of eco-friendly products such as bioplastics has been studied. This study focuses on the production of PHA using cashew industry wastewater (CIW). Since cashew industry wastewater (CIW) is rich in phenolic compounds and other sources, this study explores the possibility of eliminating the toxic phenol compounds from the waste by the production of PHA using cashew industry wastewater as a secondary source of carbon by paving the way to eco-friendly process. In this context, PHA-producing bacterium was isolated from wastewater samples collected from cashew industries. The morphological, microscopic, and biochemical characterization revealed that the isolated strain CFM1 is Bacillus sp. The strain CFM1 that gave maximum (30%) PHA in control medium was taken up for further studies with wastewater. The concentration of sucrose in the control production media was replaced with cashew industry wastewater. Wastewater was introduced to the medium at different concentrations (10–100%). As CIW concentration was increased, the sucrose concentration was decreased in the medium accordingly. CFM1 isolates produced 34% PHA with 20% wastewater. The biopolymer produced was characterized by FTIR and NMR.