Optimization of lipid production in Tetradesmus dimorphus using response surface methodology using tannery wastewater for biodiesel production

The management of industrial wastewaters and generation of sustainable energy resources are the two major challenges concerned with the global population and depleting fossil fuels. Tannery wastewater (TWW) is a major source of environmental pollution and human health hazardous if released without adequate treatment. The microalgal treatment of TWW among other approaches seems to be beneficial and effective as microalgae use TWW as nutrient source offering wastewater treatment while producing large biomass for biofuel production. Biomass and lipid content are the adequate criteria for higher biodiesel yield. In present study, Tetradesmus dimorphus was grown in TWW with an objective to treat TWW along with the generation of large biomass for biodiesel production and Response Surface Methodology (RSM) was used to optimize the biodiesel production taking into count the parameters such as wastewater concentrations, pH and photoperiod. Results showed that highest biomass and lipid content produced were 1.63 ± 0.02 g/L and 487 ± 11 mg/L, respectively with 213.80 ± 7 mg/L of biodiesel production. Gas Chromatography-Flame Ionization Detection (GC-FID) analysis of biodiesel obtained from Tetradesmus dimorphus lipids showed that it was made up of more than 40 % Methyl decanoate (C11:0) and Methyl erucate (C22:1). The interrelationships between selected parameters like STTWW concentrations, pH and photoperiods reflected the positive impact on lipid productivity as 3D contour depicted the maximum yield at 80 % wastewater concentration, pH 8 and 14 h of photoperiod. Study showed that microalgal treatment of TWW among the other approaches seems beneficial and effective to harness wastewater nutrients while producing valuable biomass for biodiesel production.