Bioresource Technology 319 (2021) 124129 Available online 17 September 2020 0960-8524/© 2020 Elsevier Ltd. All rights reserved. Short Communication Cultivation of diatom Pinnularia saprophila for lipid production: A comparison of methods for harvesting the lipid from the cells Mohd Jahir Khan a , Nisha Bawra a , Aayush Verma a , Vikas Kumar b , Arivalagan Pugazhendhi c , Khashti Ballabh Joshi b , Vandana Vinayak a, * a Diatom Nanoengineering and Metabolism Lab (DNM), School of Applied Sciences, Dr. Harisingh Gour Central University, Sagar, MP 470003, India b Department of Chemistry, School of Chemical Science and Technology, Dr. Harisingh Gour University, Sagar, MP 470003, India c Innovative Green Product Synthesis and Renewable Environment Development Research Group, Faculty of Environment and Labour Safety, Ton Duc Thang University, Ho Chi Minh City, Viet Nam HIGHLIGHTS G R A P H I C A L ABSTRACT • Rigid silica wall makes harvesting of lipid from diatoms very diffcult. • Centrifugation technique was slow, least cell death for reasonable lipid harvest. • Pulse electric feld was rapid but highly sensitive to cell lysis. • Resonance energy slow, gave maximum lipid but needs economical scale up. A R T I C L E INFO Keywords: Centrifugal force Diatoms Lipid Pulse electric feld Resonance energy ABSTRACT The present study underlines the application of centrifugal force and pulse electric feld techniques along with its comparison to resonance energy to harvest lipid from a fxed number of Pinnularia saprophila cells. Sulpho phospho vanillin method for lipid, and analysis of cells via microscopy was done. It was found that a centrifugal force of 11110×g for 15 min allowed ~3.39% lipid to ooze out with 2.5% cell destruction. Alternatively, when same numbers of diatom cells were subjected to pulse electric feld at 110 kV/27 mA for 10 µs, maximum lipid production of 2.86% with 21.19% cell death was observed. It was perceived that diatom cells in a micro reso- nating micro fuidic chamber for 20 min harvested 4.4% of lipid with 11.16% of cell death. However, micro- fuidic device needs to be scaled up using cheaper material instead of silicon wafer, to be an effcient technique to milk lipid from diatoms. 1. Introduction Diatoms are responsible for fxing 25% of global CO 2 , and produce 10 times more lipid per hectare than normal oil yielding plants (Arif et al., 2020). Photobioreactors (PBRs) which are operated for harvesting and extracting biofuel and carotenoids from algae entail huge energy (Lu * Corresponding author. E-mail address: vvinayak@dhsgsu.edu.in (V. Vinayak). Contents lists available at ScienceDirect Bioresource Technology journal homepage: www.elsevier.com/locate/biortech https://doi.org/10.1016/j.biortech.2020.124129 Received 8 August 2020; Received in revised form 10 September 2020; Accepted 12 September 2020