The Characteristics Of Chlorococcum Pamirum Under Different Mediums And Culture Methods

In recent years, microalgae have attracted big attention of people. Most microalgaehave higher oil contents、unsaturated fatty acid and other valuable compositions. Butthese components have big change in response to various culture conditions. In thisstudy, the effect of the different medirum and culture methods on Chlorococcumpamirum was investigated in order to find the sensitivity characteristics ofChlorococcum pamirum. It may provide a theoretical basis for the Chlorococcumpamirum as a bioenergy feedstock.This study included three aspects.1、Investigate the effects of different culturemedium on oil content and fatty acid composition of Chlorococcum pamirum. The sixmediums was rational designed which was BG-11、BG-11-N(nitrogen deficiency)、BG-11-P(phosphate deficiency)、BG-11-N-P(nitrogen and phosphate deficiency)、waterjust with A5and distilled water.2、The effect of nitrogen deficiency in culture outdoorcondition on Chlorococcum pamirum.3、Research the heterotrophic cultivation ofChlorococcum pamirum. The main conclusions are:（1）、The Chlorococcum pamirum in BG-11produced the biggest dry weight with7.6g/L,the Chlorococcum pamirum in other medium produced a similar dry weightnearly1.6g/L except in phosphate deficiency was2.2g/L. The oil content ofChlorococcum pamirum in BG-11、BG-11-N、BG-11-P、BG-11-N-P、A5and distilledwater is nearly30%、60%、43%、70%、70%and70%.（2）、The major fatty acids detected include C16:0, C18:0, C18:1, C18:2andC18:3. The nitrogen deficiency can increase the content of C16and decrease of thecontent of C18. Cells tend to improve the degree of saturation of fatty acids and lowerthe unsaturaion fatty acids in response to N-starvation. The cells in B、D、E、F groupwere rich in saturated fatty acid (more than60%). In unsaturated fatty acid, thedecrease almost occured in polyunsaturated species and no change in monounsaturatedspecies. Not all algal oils are satisfactory for biodiesel production, but suitable oils dooccur commonly. The fatty acid profiles of Chlorococcum pamirum in the six groupswere mainly16to18carbon atoms, which are suitable for biodiesel production. Thelipid quality analyzed in both groups suggests that a biodiesel derived from these oilsmay present an acceptable CN (cetane number), LCSF and CFPP. It is suggests thepotential of Chlorococcum pamirum as a biodiesel feedstock.（3）、Under nitrogen deficiency condition, chlorophyll-a dropped sharply in shottime and the carotenoids content decrease too. Phosphate deficiency also slight decreasethe chlorophyll-a content and increase the carotenoids content.（4）、The photosynthetic oxygen evolution of Chlorococcum pamirum cells takenfrom all groups was measured during8days and the end of culture time. The cells inBG-11-N-P obtain the highest photosynthetic oxygen evolution. Other mediums exceptBG-11-P all have a higher photosynthetic oxygen evolution than BG-11. （5）、Due to differences in light and temperature, the outdoor culture produced alower dry weight and lower percentage of oil content of dry weight compared to theindoor cultures. The thin flat plate photobioreactor(10cm) produced higher dry weightthan the thick flat plate photobioreactor(20cm). The oil accumulate rate of outdoorculture is more slowly than indoor culture, while the fatty acids composition wasunaffected to much. The pH was observaed to be influence by the temperature. Thechlorophyll-a in outdoor culture is dropped like indoor culture but the rate is slower.The photosynthetic oxygen evolution of Chlorococcum pamirum cells in thin flat platephotobioreactor(10cm) is higher than in the thick flat plate photobioreactor(20cm).（6）、Glucose is more suitable than NaCH3COOH as heterotrophic carbon sourceof Chlorococcum pamirum and the suitable glucose concentration is5g/L.