Abstract

OVERVIEW ON CULTURE OF Dunaliella salina FOR INDUCTION AND EXTRACTION OF β-CAROTENE IN KUWAIT

Tawfiq Abu-Rezq*, Suad Al-Hooti, Dangly Jacob, Mustafa Al-Shamali, Anwar Ahmed, Nisar Ahmed and Musaad Al-Roumi
*Aquaculture, Fisheries and Marine Environmental Department, Food Resources and Marine Sciences Division, Kuwait Institute for Scientific Research, P.O.Box 1638 Salmiya 22017, Kuwait. e-mail: taburezq@kisr.edu.kw

The objective was to develop a procedure to mass culture locally isolated Dunaliella salina, as a step towards enhancing β-carotene induction, and then testing and adopting a suitable method for β-carotene extraction.

A training program was attended by the Project Leader on Dunaliella salina culture and β-carotene extraction methods at Murdoch University in Perth, Australia. A field visit to Hutt Lagoon in Geraldton was also included. Professor Borowitzka supervised the training course.

It was possible to maintain pure cultures of two samples (i.e., locally isolated D. salina and a D. salina sample brought from Australia). The results of the experiments showed that both samples preferred high salinities (45 psu), low temperatures (20ºC), high light intensities (18x103 lux), and high pH levels of up to 9.18 (without using CO2 gas), for optimum growth.

Results also showed that the two samples tended to change cell color from green to brown (indicating β-carotene induction) under certain culturing conditions as follows: low culturing media concentrations; high salinity (200 to 250 psu), high temperature (38.5ºC); and high light intensity (>55x103 lux).

The positive results obtained related to β-carotene extraction indicated that the pressurized fluid extraction (PFE) and the high-performance liquid chromatography (HPLC) methods used in this study were suitable for extracting β-carotene from D. salina under laboratory conditions. These results also showed that both the D. salina samples, (Kuwaiti and Australian) contained relatively good amounts of total carotene (36.19 and 33.75 pg/cell, respectively). Due to the success and encouraging results obtained in that project, second project phase was recommended and initiated using 16 m3 indoor shallow raceways under relatively controlled conditions to test any problems that could be faced due to, e.g., dust storms, growth of predators or competitors as a further step toward commercialization.