The production of biofuel and bioelectricity associated with wastewater treatment by green algae

Abstract

This study describes algal biofuel production, bioelectricity generation and wastewater treatment using Leptolyngbya sp. JPMTW1 (KF977831). The experiments were conducted in an AMFC (Algal Microbial Fuel Cell) photobioreactor (single-chamber). The pH, EC (electrical conductivity), COD (chemical oxygen demand) and TDS (total dissolved solids) decreased from 8.01 to 7.0, 982 to 854 (mS/cm), 255 to 112 (mg/L) and 490–427 (mg/L), respectively, over course of 7 days. Biomass production, rate of biomass production, chlorophyll a, b and “total chlorophyll” content increased with increasing time and were observed to be 3300 mg/L, 471.42 mg/L/day, 0.981 mg/L, 0.173 mg/L and 1.156 mg/L after 7 days. Lipid production and rate of lipid production were 1068.383 mg/g dry wt. biomass and 152.62 mg/g dry biomass/day. FTIR (Fourier transform infrared) spectra revealed the presence of protein, lipid, FAs (fatty acids), triglycerides and ester functional groups. FAME (fatty acid methyl esters) profile revealed the presence of C16:0, C18:2n-6, C18:1 and C16:1. The generation of electric potential by Leptolyngbya sp. JPMTW1 increased significantly (p ≤ 0.05) from 0.0211 to 0.264 mV within 7 days. The maximum power density (0.008 mW/cm2) was obtained at cell potential at 12 mV. This study shows that simultaneous production of biofuel, bioelectricity and wastewater treatment is possible by Leptolyngbya sp. JPMTW1.