Utilization of microalgae for self-regulation of extracellular polymeric substance production

Abstract Extracellular Polymeric Substance (EPS) production in relation to carbohydrate and protein compositions is an important key in wastewater bio-treatment and microalgal harvesting. The influence of microalgal cultivation conditions on EPS production is well-documented in previous studies, but there continues to be a research gap that involves the effect of the initial concentration of microalgae added in media culture. This study aimed at investigating the impact of various initial microalgae concentrations on the behavior of carbohydrate and protein compositions constituting EPS. This study is important as it helps to enhance EPS production that associate with its applications. The total carbohydrate on average obtained was 31.1 mg L−1 and protein 25.6 mg L−11. Results revealed that the compositions of carbohydrates and proteins were not regulated by initial concentrations of microalgae. However, the difference in the behaviour of the EPS is noticed in the loosely bound-EPS (LB-EPS) and tightly bound-EPS (TB-EPS). The dominant production of carbohydrates in LB-EPS was approximately 2.2 times higher than in TB-EPS. As a conclusion, it was found the effect of monosaccharide fraction was primarily derived by glucose and arabinose components in both layers. The contents of monosaccharide components were analytically stable around 21.70 mg. L−1 after their self-regulation except for glucose in LB-EPS.