Sustainable bioremediation of cassava waste effluent using Nannochloropsis salina TSD06: an eco-technological approach

Abstract

Abstract This present study explored the large-scale treatment of cassava effluent using the freshwater green microalga Nannochloropsis salina TSD06. The cassava effluent treatment exposed a significant reduction of the inorganic pollutants were 98.26% nitrate, 93.94% phosphate, 97.43% sulfate, 85.86% chloride, 94.73% calcium, 93.45% potassium, 93.1% magnesium, 98.32% of sodium and 97.36% of phosphorus on 10th-day treatment using Nannochloropsis salina TSD06 microalga under optimized conditions. The analysis of variance (ANOVA) was performed utilizing response surface methodology (RSM), and experimental results showed a high regression coefficient (R2 = 0.999). The experimental microalga produced 7.25 mg/mL of biomass, 276.65 mg/g of lipids, 125.34 mg/mL of carbohydrates, and 3.75 mL/g of biodiesel. The Nannochloropsis salina TSD06 microalga produced biodiesel compounds were analyzed through gas chromatography-mass spectrometry (GCMS) and identified the major compounds viz., 13.45% of oleic acid, 11.84% of stearic acid, 10.23% of myristic acid, 9.45% of palmitic acid, 8.31% of linoleic acid, 8.04% of hexadecanoic acid, 7.62% of eicosadienoic acid, 4.86% of octadecanoic acid and 3.19% of docosahexaenoic acid. The functional groups were revealed from biodiesel using Fourier transform infrared spectroscopy (FTIR) analysis, and the functional groups were carboxyl groups, phenol molecules, alcohol molecules, alkenes, and carbonyl groups. The Nannochloropsis salina TSD06 microalga showed high removal ability and provided an effective, eco-friendly method of wastewater treatment and biofuel production.

Keywords

• Biodiesel
• Cassava effluent
• Fourier transform infrared spectroscopy
• Gas chromatography mass spectrometry Nannochloropsis salina TSD06
• Photo bioreactor
• Response surface methodology