Growth promoting studies on co-culturing Nannochloropsis oceanica with Halomonas aquamarina actively enhance the algal biomass and lipid production

Abstract

Photosynthetic macroalgae plays a major role in capturing solar energy and convert it to bioenergy in the marine environment, thereby releases the potential bioactive constituents. Microalgae live together with the bacterial community in nature via symbiotic relationship. We investigated the symbiotic association of microalgae-bacteria and their response towards adaptation by producing siderophores as well as other bioactive principles. Microalgae Nanochloropsis oceanica were cultured under controlled conditions and the resulting associated microbe was found to be Halomonas aquamarina. Interestingly, the bacteria H. aquamarina promoted the microalgal growth faster at day 7 (1.09 × 107 cells/ml) as compared to the control at day 12 (1.72 × 106 cells/ml) respectively. Furthermore this co-culture system acts as an effective growth promoter of hydroxamate siderophores (69.97 μg/ml) that enhanced algal biomass and lipid contents (30.92117 μgL−1) than the control (24.86428 μgL−1). Pigment profiling of N. oceanica by HPLC revealed that H. aquamarina does not affect the algal signature pigments rather it enhanced the pigments concentration. The present study provides a knowledge on the biological interaction of microalgae-bacteria as an efficient tool to improve the biomass yield with reduced cultivation costs. Moreover, the consideration of symbiosis between microalgae-bacteria is likely to have insightful effects for the future exploitation of microalgae in the field of agriculture, pharmaceutical and biotechnological applications.