Wasana Arkronrat, Prapapron Deemark, and Vutthichai Oniam

DOI: 10.14456/sjst-psu.2016.1

pp. 1 - 5

Abstract

The growth performance and proximate composition of two marine microalgae, Nannochloropsis sp. and Tetraselmis
sp., in monoculture and mixed culture of both species under laboratory conditions were compared. Microalgae were cultured
in enriched seawater (28 ppt) in 8 L plastic bottles using Conway medium. Microalgae were grown in a temperature-controlled
room (25°C) under continuous illumination at a light intensity of about 3,000 Lux for 240 hours (10 days). Results showed that
maximum cell density and growth rate of both species (45.06±2.67×10⁵ cells ml^-1 and 0.43±0.02 day^-1, reps.) in mixed culture

had a significantly higher than Tetraselmis sp. (5.09±0.99×10⁵ cells ml^-1 and 0.16±0.03 day^-1, reps.), but not significantly
different with Nannochloropsis sp. (29.25±22.70×105 cells ml^-1 and 0.37±0.14 day^-1, reps.) in monoculture. For proximate
composition, protein content of both species in mixed culture and Nannochloropsis sp. in monoculture was significantly
higher than for Tetraselmis sp. in monoculture after 120 and 240 hours of cultivation. Carbohydrate and lipid contents of
each treatment were found to be significantly different after 120 hours of cultivation but not significantly different after 240
hours of cultivation. Therefore, this study indicates that an alternative option for commercial microalgal production is to use
a mixed culture to obtain higher production.