Cultivation of a marine diatom, Amphora sp., in municipal wastewater for enhancing lipid production toward sustainable biofuel production
Anandapadmanaban Baala Harini, Naduvil Veettil Sarangi, Natarajan Nisha, Renganathan Rajkumar
Abstract
• Isolation of marine diatom, Amphora sp. with high lipid productivity was achieved. • Biomass and lipid production by Amphora grown in municipal wastewater was evaluated. • FTIR , GCMS and 1 H NMR were performed to study the fatty acid methyl ester content. • Microalgae cultivation with wastewater helps to improve the economic viability of biofuel. Municipal wastewater contains a high amount of nutrients, which are suitable to cultivate microalgae. This wastewater is considered a potential nutrient source for microalgae cultivation in order to reduce the manufacturing cost for biodiesel production. The present study was focused on the growth and lipid accumulation of newly isolated marine diatom by using municipal wastewater as a culture medium. This diatom was identified as Amphora sp. RRSE1 based on its morphological and molecular characteristics. The optimal medium consists of 80% municipal wastewater mixed with 20% standard De Walne's medium, at pH 8 was supported on the maximum growth and lipid production. It was observed that the peak concentration of biomass was 17.225 mg/L, corresponding to the productivity of 1.46 mg/L/day. The lipid concentration of the biomass was 10.9 mg/L, which shows the maximum productivity of 0.92 mg/L/day. The highest lipid content of 63.12% was achieved on the 14 th day of culture. Moreover, Fourier Transform Infrared Spectroscopy (FTIR) was performed for the qualitative and quantitative analysis of organic and inorganic compounds present in the biomass samples. In addition to that, Gas chromatography and mass spectrometry (GCMS) and 1 H NMR analyses were also achieved to study the fatty acid methyl ester on the extracted lipids. This study indicates that the microalga Amphora sp. RRSE1 is capable of utilizing nutrients from municipal wastewater and this strain could be a promising feedstock for biofuel production. Furthermore, the use of municipal wastewater as a supplement in nutrient media can greatly reduce the microalgal production costs.