Journal of Pure and Applied MicrobiologyVol. 8 No. 6

Purification of Dunaliella salina and Effects of Associated?Bacteria on its Physiological and Biochemical Characteristics

Ying Tang, Di Huang, Chang Hai Wang* and Li Ming Ma

School of Life Science and Biotechnology, Dalian University of technology, Linggong Road 2, Dalian, Liaoning, 116024, China.

Received on 06 April 2014 and accepted on 19 August 2014

 

ABSTRACT

Investigations of microalgae-bacteria relationship are important to studies of microbial ecology, red tide, aquaculture and pollutant degradation, etc. To date, microalgae-bacteria interactions are still not well understood, and purification of eukaryotic microalgae is also rarely mentioned. Here, bacteria-free Dunaliella salina was obtained with optimized antibiotic treatments. Axenic microalgal growth did not differ significantly with non-axenic algae in f/2 medium. However, when the contents of nitrogen and phosphorus were 10-fold higher of f/2, or there were no vitamins or trace elements in f/2 medium, the non-axenic algae grow much faster-increased 6.78%, 10.25% and 10.19% than axenic algal biomass, respectively. Associated bacteria haven?t significant effect on microalgal intracellular gross fat and ash contents, while improved microalgal intracellular protein and intra- and extra-cellular total carbohydrate contents during most growth stages. Associated bacteria didn?t impact algal nitrogen uptake. While under high nutrient concentration conditions, the phosphorus contents decreased more rapidly in non-axenic algal culture (decreased 40.48%) than in axenic algal culture (decreased 5.99%) within the first 4 days, suggesting that non-axenic algal phosphorus uptake was stronger. The study provided a simpler system and effective references to research of microalgae-bacteria relationship.

Keywords : Antibiotics; Bacteria-microalga interaction; Biochemistry composition; Dunaliella salina; Inorganic nutrients uptake; Purification.