Enhanced Production of High-Quality Biomass, δ-Aminolevulinic Acid, Bilipigments, and Antioxidant Capacity of a Food Alga Nostochopsis lobatus

Abstract

The growing interest in natural food has raised the global demand for nutraceuticals. We studied enhanced production of biomass, delta-aminolevulinic acid (δ-ALA), bili pigments and antioxidant capacity of a food alga Nostochopsis lobatus in a full-factorial (three level) design with supplemental Zn, glutamine, and Zn + glutamine in batch culture. Production of biomass, pigments, and antioxidant capacity all were higher under immobilized cell cultures in comparison to free cell cultures. Maximum biomass (2,390 mg dry wt l⁻¹), δ-ALA (2.715 μg mg⁻¹ dry wt h⁻¹), phycocyanin (98.50 mg g⁻¹ dry wt), phycoerythrin (158.0 mg g⁻¹ dry wt), and antioxidant capacity (140.50 μmoles ascorbic acid equivalent capacity g⁻¹ fresh wt) were recorded when Zn and glutamine were supplemented together in the growth medium at pH 7.8. These effects were found to be significantly related to the activities of glutamine synthetase (GS_max: 490.2 nmoles mg protein⁻¹ min⁻¹), glutamate synthase (GOGAT_max: 27.0 nmoles mg protein⁻¹ min⁻¹), and glutamate dehydrogenase (GDH_max: 159.9 nmoles mg protein⁻¹ min⁻¹). This study shows that N. lobatus could be a promising bioresource for the production of nutritionally rich biomass, δ-ALA, bili pigments, and antioxidants. Use of immobilized cells in batch culture supplemented with Zn and glutamine could be an effective approach for scaling up production for commercial use.