Extraction and optimization of biomolecules recovery from Chlorella sp. NITT 02: Unleashing potential through ultrasound and triphasic system of extraction

Microalgae are photosynthetic microorganisms that have the capacity to synthesize a diverse range of biomolecules depending on their phylogenetic classification. Microalgae hold promise as sustainable and renewable energy resources; however, their full potential remains untapped due to the costliness and time-intensive nature of downstream processing. The objective of this study is to overcome these challenges by utilizing a single processing unit for the extraction of three major biomolecule classes namely, lipids, proteins, and carbohydrates. These biomolecules of marine Chlorella sp. NITT 02 were recovered in a single extraction process using the triphasic system. The parameters defining the triphasic system were optimized for the maximum recovery of biomolecules using Response Surface Methodology (RSM) coupled Genetic Algorithm (GA) optimization. The simultaneous complete recovery of lipids with 86.46 % of total fatty acids, 97 % protein recovery and 97.1 % carbohydrate recovery were obtained with i) 2.5:1 of t-butanol:culture volume, ii) 70 % t-butanol, iii) 32.9 % ammonium sulfate, and iv) 55 min sonication time. All three extracted biomolecule classes were characterized using FTIR, GC-MS, UV-Visible spectrophotometry, and XRD. From the current investigation, the recovery efficiency of the triphasic system is higher than the conventional sequential extraction of biomolecules and the time taken for extraction is 1.25 h with energy consumption of 0.7833 kWh. Hence, the adoption of this biorefinery approach is suitable for making microalgae commercially viable for producing valuable products from the biomolecules.