Relationship Between Total Phenolics Content and Antioxidant Activities of Microalgae Under Autotrophic, Heterotrophic and Mixotrophic Growth

Research Article
Relationship Between Total Phenolics Content and Antioxidant Activities of Microalgae Under Autotrophic, Heterotrophic and Mixotrophic Growth

Journal of Food Resource Science, 2015, 4(1), 1-9.

Abstract

A study was carried out to explore the relationship between growth conditions and antioxidant properties of microalgae. Further, correlation between phenolics and antioxidant activities were studied to determine whether antioxidant activity depends on microalgal phenolics content under varying culture conditions. Total phenolics and antioxidant properties of Chlorella vulgaris and Scenedesmus obliquus grown under autotrophic, heterotrophic and mixotrophic conditions were evaluated. Domestic water, Bold’s medium and sewage water were used to cultivate the microalgae and the extracts were prepared in methanol and analyzed for biochemical (total phenolics) and antioxidant properties (DPPH assay, super oxide scavenging assay and antioxidant potential). The experiments were done in triplicates and significant correlation coefficients between antioxidant properties against phenolic content and growth conditions were interrelated. The amount of total phenolics content varied in growth conditions and ranged from 0.11-0.55 mg GAE g^-1. Significant correlation co-efficient between phenolics and antioxidant properties of microalgae determined by DPPH, superoxide anion scavenging and total antioxidant activities were found in the study. The strongest positive correlation was found to be between total phenolics and DPPH activity in C. vulgaris (r = 0.997). In S. obliquus, the strongest positive correlation was between total phenolics and antioxidant potential (r = 0.091) at p<0.01 followed by superoxide scavenging (p<0.05). The findings indicated that phenolic compounds were the major contributors to the antioxidant properties of microalgae. The results demonstrated that strongest positive correlation was observed in mixotrophic conditions followed by autotrophic conditions in Chlorella whereas the correlation was significant under heterotrophic conditions in Scenedesmus followed by mixotrophic conditions.

ASCI-ID: 5150-12

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