Comparison of subcritical fluid extraction and microwave-assisted extraction of phenolic compounds from Chlorella sorokiniana

• Main Authors: Burog, Frechette Anne P., Ngo, Krishel Eunice O., Rentuza, Kiara Denesse A.
• Format: text
• Language: English
• Published: Animo Repository 2022
• Subjects: Chlorella sorokiniana; Phenols; Feedstock; Chemical Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etdb_chemeng/16; https://animorepository.dlsu.edu.ph/cgi/viewcontent.cgi?article=1010&context=etdb_chemeng
• Institution: De La Salle University

The potential benefits of phenolic compounds as functional ingredients are currently studied to serve as replacements to synthetically derived compounds. The presence of these compounds in microalgae and the abundance in the environment makes these microorganisms a viable feedstock for extraction. Chlorella sorokiniana is one of the promising feedstocks for extraction due to its tolerance to extreme stresses which may result in higher production of phenolic compounds. This study aimed to investigate the presence of phenolic compounds in C. sorokiniana using non-conventional methods of extraction particularly, subcritical fluid extraction (SCF) and microwave-assisted extraction (MAE). The experiment was carried out with the following parameters: subcritical temperature (100 and 140C), microwave temperature (60 and 90C), and solvent type (water and 90% ethanol). After the extraction, the total phenolic content (TPC) of the samples were determined using Folin-Ciocalteu method against known concentration of gallic acid standard. It was observed that increasing the temperature results to a higher yield for both SCF and MAE. However, this was not true for the MAE sample (90% ethanol, 90C) due to the evaporation of the solution. In terms of solvent type, 90% ethanol extracted more phenolic compounds compared to water. The highest total phenolic content was observed at 60C temperature, 90% ethanol solvent, and MAE as the extraction method with a value of 20.28 ± 1.31 mg GAE/g biomass. With a confidence level of 95%, the effect of temperature is significant in both MAE and SCF. The effect of type of solvent and the interaction between solvent type and temperature are also significant in MAE. Furthermore, the R2 value of the models for SCF and MAE are found to be 0.7490 and 0.9535, respectively. Hence, this study has identified, within the experimented parameters, the best set that gave the highest extraction yield of phenolic compounds from Chlorella sorokiniana.