Analysis of the remediation competence of Aspergillus flavus biomass in wastewater of the dyeing industry: An in-vitro study.

The dyeing industry effluent causes severe environmental pollution and threatens the native flora and fauna. The current study aimed to analyze the physicochemical parameters of dyeing industry wastewater collected in different sites (K1, E2, S3, T4, and V5), as well as the metal tolerance and decolourisation ability of Aspergillus flavus. Furthermore, the optimal biomass quantity and temperatures required for efficient bioremediation were investigated. Approximately five dyeing industry wastewater samples (K1, E2, S3, T4, and V5) were collected from various sampling stations, and the majority of the physical and chemical characteristics were discovered to be above the permissible limits. A. flavus demonstrated outstanding metal resistance to As, Cu, Cr, Zn, Hg, Pb, Ni, and Cd on Potato Dextrose Agar (PDA) plates at concentrations of up to 500 g mL-1. At 4 g L-1 concentrations, A. flavus biomass decolorized up to 11.2-46.5%. Furthermore, 35°C was found to be the optimal temperature for efficient decolourisation of A. flavus biomass. The toxicity of 35°C-treated wastewater on V. mungo and prawn larvae was significantly reduced. These findings indicate that the biomass of A. flavus can be used to decolorize dyeing industry wastewater.

Sugar cane bagasse hydrolysate (SBH) as a lucrative carbon supplement to upgrade the lipid and fatty acid production in Chlorococcum sp. for biodiesel through an optimized binary solvent system.

Cost is the crucial impediment in commercializing microalgal biodiesel. Therefore, cultivating microalgae in cost-effective nutrients reduces the upstream process cost remarkably. Thus, in this study, sugar cane bagasse hydrolysate (SBH) as a lucrative carbon supplement for Chlorococcum sp. and subsequent lipid extraction via an optimized solvent system for biodiesel production was investigated. Characterization of SBH revealed the presence of various monosaccharides and other sugar derivatives such as glucose, fructose, xylose, arabinose, etc. The maximum dry cell weight of 1.7 g/L was estimated in cultures grown in 10 mL SBH. Different solvents such as diethyl ether (DEE), chloroform (CHL), ethyl acetate (ETA), hexane (HEX), methanol (MET), ethanol (ETOH), acetone (ACE) and also combination of solvents (2:1 ratio) such as DEE: MET, CHL: MET, HEX: MET, HEX: ETOH was tested for lipid extraction efficacy. Among solvents used, 12.3% and 18.4% of lipids were extracted using CHL and CHL: MET, respectively, from 10 mL SBH amended cultures. However, the biodiesel yield was found to be similar at about 70.16 % in both SBH and no SBH-added cultures. The fatty acid profile of the biodiesel shows palmitic, oleic, linoleic, linolenic, and arachidonic acid as principal fatty acids. Further, the levels of SFAs, MUFAs, and PUFAs in 10 mL SBH-added cells were 24.67, 12.89, and 34.24%, respectively. Eventually, the fuel properties of Chlorococcum sp. biodiesel, satisfying international biodiesel standards, make the biodiesel a viable diesel substitute in the future.