Variation of both chemical composition and antioxidant properties of newly isolated Parachlorella kessleri GB1, by growing in different culture conditions

Abstract

The purpose of this study was to investigate the effect of variation of different cultivation mode (autotrophic, mixotrophic and heterotrophic) on biomass productivity, cellular composition and in vitro antioxidant activities of Parachlorella kessleri GB1. The biomass productivity at mixotrophic (M20 using 20 g/L glucose and light) and heterotrophic (H20 using 20 g/L glucose) conditions were higher than autotrophic cultivation mode by 8.2 and 7.9 fold, respectively. Total phenolic contents of dried cell weight were significantly different (P < 0.05). Mixotrophic cultivation mode using 20 g/L glucose showed highest 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation scavenging activity (2.96 ± 0.07 μmol trolox/g), phosphomolybdenum (PM) antioxidant properties (4.35 ± 0.06 ascorbic acid equivalent (AAE) mg/g), with phenolic content (7.39 ± 0.20 mg gallic acid equivalent (GAE)/g). The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and ferrous chelating activity properties exhibited dose dependency. The EC50 of 0.073 ± 0.001 and 0.074 ± 0.001 mg/mL for DPPH radical scavenging effect was found in mixotrophic (M20) and heterotrophic (H20) cultivation mode, respectively. The algal cultivation in mixotrophic and heterotrophic cultivation mode offers higher biomass productivity, protein, and antioxidant enriched bioactive substances compared to the autotrophic cultivation mode. Overall, these results shows that cultivation methods and the bioactive properties could also be important criteria for quality control and categorizing premium quality algal biomass.