SUSTAINABLE INDUSTRIAL AND ENVIRONMENTAL BIOPROCESSES Biological fixation of carbon dioxide and biodiesel production using microalgae isolated from sewage waste water Neha Maheshwari 1 & Pushpa K Krishna 1 & Indu Shekhar Thakur 2 & Shaili Srivastava 1 Received: 1 February 2019 /Accepted: 8 July 2019 # Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract The present research investigates potential of microalgae isolated from sewage treatment plant to utilize sodium bicarbonate as carbon source for CO 2 sequestration and biodiesel production. Eight algal isolates were isolated from waste water of sewage treatment plant, Amity University Haryana, India. The most potent algal isolates were identified and characterized on the basis of growth and lipid content. The efficient isolates ASW1 and ASW2 were identified as Chlorella sp. and Arthronema sp. by 18srRNA and 16srRNA sequencing method. In both isolates, maximum growth was observed under 20-W fluorescent bulb (3500 flux light intensity) with continuous light cycle of 24 h at pH 9.0 and 25 °C on the 20th day of incubation period. CO 2 utilization efficiency of both algal isolates were observed in terms of total CO 2 consumption rate. Under optimized culture conditions, total lipid content and lipid yield was higher in Arthronema sp. (180 mg l -1 ; 32.14%) as compared to Chlorella sp. (98 mg l -1 ; 29.6%) in 50 mM NaHCO 3 . Transesterified lipids were analysed by GC-MS. The fatty acid methyl ester profile of Arthronema sp. was 34.42% saturated and 65.58% unsaturated fatty acid. Chlorella sp. produces 29.80% saturated and 70.20% unsaturated fatty acid. In both isolates, C16 and C18 fatty acids dominated, which is a promising component for biodiesel. Keywords Chlorella sp. . Arthronema sp. . CO 2 sequestration . Fatty acid methyl esters . Biodiesel Introduction The emission of carbon dioxide (CO 2 ) into the atmosphere has become the major environmental concern. The increase rate of CO 2 emission is resulting from the combustion of fossil fuel and industrial development (Pachauri and Reisinger 2007; Zhang and Liu 2012). Many technologies have been developed to reduce the emissions of CO 2 into the atmosphere but fixation of CO 2 by autotrophic plants and algae is the most sustainable method. Biological fixation of CO 2 byphotosynthetic organism is of interest due to re- duction of atmospheric carbon content from the environ- ment. Photosynthetic organisms are a potential alternative to convert atmospheric CO 2 into biomass which further uti- lized to generate energy in the form of biofuel (Rivera et al. 2018; Jana 2019; You et al. 2019). Microalgae and cyanobacteria like Coelastrum sp. SM, Anacystis , Botryococcus, Gracilariopsis, Chlamydomonas, Chlorella vulagris , Emiliania , Monoraphidium, Rhodobacter, Scenedesmus obliquus and Synechococcus have been char- acterized for CO 2 fixation and biofuel production (Melis 2009; Weyer et al. 2010; Tripathi et al. 2015; Mishra et al. 2018; Chaudhary et al. 2018; Mousavi et al. 2018; Liu et al. 2018). Microalgae have several benefits over feedstock crop plant for mitigation of CO 2 as well as biofuel production. Microalgae can grow in different habitats like marble rocks, fresh water, marine water and wastewater, where other feed stocks cannot inhabit in extreme conditions (Searchinger et al. 2008; Wang et al. 2008; Tripathi et al. 2015; Singh and Dhar 2019).Generally, microalgae have greater photo- synthetic efficiency and higher ability of CO 2 capture at low concentration and conversion into biomass (Melis 2009; Weyer et al. 2010; Tripathi et al. 2015; Mishra et al. 2018). Algal biomass can be controlled and optimized by parameters such as light, nutrients, temperature and salinity (Chang and Yang 2003). Responsible editor: Ta Yeong Wu * Shaili Srivastava shailisrivastava05@gmail.com 1 Amity School of Earth and Environmental Science, Amity University Haryana, Gurugram, India 2 School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India Environmental Science and Pollution Research https://doi.org/10.1007/s11356-019-05928-y