Isolation and Culture Condition Optimization of Chlorella vulgaris

Chlorella vulgaris Beyerinck (Beijerinck) is one of the fast growing planktonic microalgae predominantly found in lentic habitats. It was isolated from water samples using BG 11 medium and identified and screened for mixotrophic growth using glucose as carbon source in the medium. The growth of this algae was also studied for autotrophic and mixotrophic regimen. It showed higher growth in a medium of pH 7 containing glucose rather than in autotrophic condition. Similarly, its growth was also studied in media containing different nitrogen sources in which NaNO3 gave the best result. A pilot scale culture of C. vulgaris was performed in 5 l fermenter illuminated with fluorescent tube of 36 W maintaining 16:8 hrs of light and dark period with pH 7, temperature at 25°C, stirrer rate at 75 rpm, air flow rate at 30 L/hr. The specific growth rate was found to be 6.879 cells/ ml/ day whereas doubling time was found to be 2 hrs and 9 mins. The cells were harvested by sedimentation and centrifugation followed by drying at 50°- 80°C. The dried biomass was treated with dichloromethane: methanol (2:1) v/v solution in Soxhlet extractor for 3 DOI: http://dx.doi.org/10.3126/njst.v14i2.10414 Nepal Journal of Science and Technology Vol. 14, No. 2 (2013) 43-48

Acclimatization of micropropagated plantlets of Coffea canephora

Coffea canephora is the predominant species in the state of Rondônia, due to its adaptation to soil and climatic conditions in the region. The acclimatization comprises a set of techniques and procedures that are designed to adapt plantlets to field conditions, heterotrophic to autotrophic condition. This work aimed to evaluate conditions of acclimatization of plantlets of C. canephora in relation to the initial stages of seedling development, levels of shading and acclimatization period. In the first experiment, we used three stages of micropropagated plants: "torpedoes", "sprouted" and "seedling" and two levels of shading, 30 and 50% in 3 x 2 factorial. The plants were weighed and placed individually in cells containing the trays Plantmax®. After 30 days, there was survival, plant length, leaf number and fresh weight. The second experiment evaluated three periods of acclimatization at 30, 45 and 60 days, after the seedlings were transferred to field conditions in plastic bags. After 90 days of the deployment of the experiment, there was survival, plant length, leaf number and the ratio between initial and final weight of the seedlings. The developmental stage "seedlings" resulted in increased survival and plant development stages in relation to "torpedo" and "sprouted." The shading of 50% resulted in increased survival and plant growth than 30%. The acclimatization period of 30 days did not differ significantly from the periods of 45 and 60 days, the most suited for this application.