MICROBIOLOGICAL AND ECOPHYSIOLOGICAL CHARACTERIZATION OF GREEN ALGAE Dunaliella sp. FOR IMPROVEMENT OF CAROTENOID PRODUCTION

An isolate of green algae Dunaliella sp. from BBAP Jepara is usually used as a source for carotenoid supplement for marine animal cultivation in the local area. In order to improve carotenoid production especially detection of biosynthetic pathway from the organisms investigated in this study, the main purpose of this study is characterizing Dunaliella sp. based on it’s microbiological and ecophysiological characters. The research was done by characterize the growth, the cell and colonies microbiologically, total pigment production, and also characterize all of the ecophysiological factors affecting the algal growth and survival. The results of this research showed that Dunaliella sp. posseses typical characteristic of green eucaryote alga, in their growth and ecological condition. The extreme characters which was toleration ability to high salinity environment of was used to conclude Dunaliella sp. as Dunaliella salina.

A local isolate of an algal species

Culture Media
The Walne medium was used for culturing Dunaliella sp.modified from Bidwell and Spotte (1983)

Microbiological and ecophysiological Characterization
Microbiological characterization was done according to Boney (1989), Sze Illumination was observed at 660 µEinstein.m-2.sec-1 or 600 lux (Rabbani et al., 1998).Measurement of pigments concentration was done by extracting the specimen with methanol or acetone to check if residual color (blue to red) caused by the non-organic soluble phycobillins remains in the cell (Goodwin and Britton, 1988;Holt et al., 1994).
Chlorophyl concentration were analyzed by extracting cell pellet with methanol until the pellet color is dissappeared.

Concentration of chlorophyll was
measured by OD 663 nm and OD 645 nm , then calculated with formulas (Harborne, 1984;Goodwin and Britton, 1988) :        , 1993).Some studies also display that green algae Dunaliella showing a remarkable adaptation to a variety of salt concentration from as low as 0,2% to salt saturation of about 35% (Borowitzka & Borowitzka, 1988;Ben-Amotz, 1993).

For
photosynthetic eukaryotes which are responsible for up to 50% of the planet's atmospheric carbon fixation.The recent discoveries of health related beneficial properties attributed to algal carotenoids have spurred great interest in their production.Carotenoids, some of which are provitamin A, have range of diverse biological function and actions, such as species spesific coloration, photo protection, and light harvesting, and they of daughter cell, cell division and rfeproduction, presence and arrangement of flagella, gliding motility, presence or lack of cell walls, presence or lack of nucleus walls, presence or lack of cell sheath.aeration and illumination, also salinity.Growth experiment was measured by cell count and cell density absorbancies at OD 600 nm .
Dunaliella sp. is freeliving organisms, unicellular and solitaire.Each cell has an ovoid space and is surrounded by a delicate wall.The flagella are smooth.A single large chloroplast in the shape of thick cup fills much of the volume of the cell.Cell was spherical or elongate in shape, widely oval before division and after division hemispherical.Cells of Dunaliella sp.swim actively by means of two anterior flagella.is non motile cells and do not have flagella.The color of the cell is bright green and turn to greenish yellow on the sixth day of growth.Cells are surrounded by narrow, fine, green colour envelopes.Cellular reproduction is by division into two morphologically equal, hemispherical daughter cells (binary fission), which reach the original globular shape before next division.Cells divide in one planes in successive generations in broth media (Fig 2).The envelopes around cells will split together with dividing cells.Daughter cells separate after division and grow into the original size and shape before next binary fission.Daughter cells held together by mucilaginous sheath.Reproduction of cell was sexual or asexually (Fig 3 and Fig 4).

of
Dunaliella sp. was carried out by growth and factor influencing growth including temperature, salinity and light.The characteristic of Dunaliella sp. are presented in Table 1.Dunaliella sp.usually live in sea water but also can water but also can survive in fresh water According to Boney (1989) Dunaliella sp.synthesizes glycerol which internally act as 'a compatible solvent' allowing enzyme activity to continue despite high concentrations in the surrounding medium.The glycerol is excreted when the cell return to lowered salinities.

Figure 4 .
Figure 4. Growth Curve of Dunaliella sp. on Walne medium photosynthetic glycerol in respons to the extracellular osmotic pressure.On growth in media containing different salt concentration, the intracellular glycerol concentration is directly proportional to the extracellular salt concentration and maintains the cell water volume and the required cellular osmotic pressure.
Figure 4. Total pigment production of Dunaliella sp.