Production of value-added Polyhydroxyalkanoates (PHA) by fungi using dairy wastewater as a carbon source

Abstract

Plastics are synthetic petrochemical-based polymers that take several decades to degrade due to their recalcitrant nature and often release numerous toxic byproducts on degradation. Alternatively, bioplastics (Polyhydroxyalkanoates (PHA)) are considered to be the best replacement for traditional plastics. They are biocompatible, environmentally friendly, biodegradable, and have physio-chemical properties similar to conventional plastics. The present study aimed to produce PHA using dairy wastewater as a substrate for microorganisms. Dairy waste is one of the common industrial wastes that needs to be properly disposed of to avoid water contamination. The PHA-producing ability of the organism was screened using Sudan Black B dye. The MSM medium amended with dairy wastewater (DWW) was used as a substrate for the organism for PHA synthesis. After incubation, the cell dry mass was measured, and PHA was extracted. The extracted PHA monomers were characterised by GC-MS analysis. The PHA-producing organism VITJK07 was identified as a Candida tropicalis species by 18S rRNA partial gene sequencing. The quantity of PHA synthesised by the organism was comparatively higher (21.4%) using dairy wastewater as a substrate than glucose (13.5%). The results of the study indicate that dairy wastewater could be used as a substrate for PHA production by the Candida species.