Polyhydroxybutyrate production by Chlorella sorokiniana SVMIICT8 under Nutrient-deprived mixotrophy

• Published in: Bioresource technology Vol. 354; p. 127135
• Main Authors: Kumari, Poonam, Ravi Kiran, Boda, Venkata Mohan, S.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.06.2022
• Subjects: 3-hydroxybutyryl-CoA; Biodegradable polymer; Chlorophyll a fluorescence; Nutrient starvation; Process optimization; Chlorophyll a fluorescence; Process optimization; Nutrient starvation; Biodegradable polymer; 3-hydroxybutyryl-CoA
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2022.127135

•Chlorella sorokiniana SVMIICT8 was cultivated in biphasic mode for PHB simulation.•Modified solvent extraction methodology was adapted for PHB extraction.•Extracted PHB exhibited structural and molecular similarities to that of commercial grade PHB.•Lipid productivity with wide-ranging FAME was witnessed. Polyhydroxybutyrates (PHBs) are naturally occurring biopolymeric compounds that accumulate in a variety of microorganisms, including microalgae as energy and carbon storage sources. The present study was designed to evaluate nature-based PHB production using microalgae (Chlorella sorokiniana SVMIICT8) in biphasic (growth (GP) and stress phase (SP)) nutritional mode of cultivation. Microalgal PHB accumulation was driven by nutrient constraint, with a maximal production of 29.5% of PHB from 0.94 gm L−1 of biomass. Fluorescence microscopy revealed PHB granules in the cell cytoplasm, while NMR (1H and 13C), XRD and TGA analysis confirmed the structure. The biopolymer obtained was homopolymer of PHB with carbonyl (C=O) stretch of the aliphatic ester moiety. In GC-MS analysis, major peak representing butyric acid methyl ester also confirmed the PHB. Chlorophyll a fluorescence transients inferred through OJIP, exhibited significant variation in photosynthetic process during growth and nutrient limiting conditions. Mining of bio-based products from microalgae cultivation embrace nature-based approach addressing climate change and sustainability inclusively.