微藻類之生質能源開發

The exploitation of bioenergy from microalgae.

蘇純平(Chun-Ping Su)

指導教授 ： ARRAY(0xa782824)

中原大學/工學院/土木工程研究所/碩士(2010年)

https://doi.org/10.6840/cycu201000541

摘要

近年來生物處理二氧化碳已逐漸受到重視，水生之微藻類將可以利用二氧化碳當作碳源，產生出來的高密度微藻，可以萃取其細胞中的單細胞油脂，將其轉化為生質柴油。
本研究選取高脂質含量之綠藻Chlorella vulgaris為研究對象，先利用連續式放大培養，再運用批次實驗將其培養在不同之酸鹼值、光照強度及二氧化碳曝氣濃度條件下，分別利用葉綠素a、光學密度、藻密度、藻細胞數與脂質含量來討論生長情形，由生長情形以及脂質含量選出最適合藻種生長之生存條件。轉酯化方法則是應用單步驟轉酯反應(One-step method)將脂肪酸轉化為脂肪酸甲酯（FAME），並運用氣相層析儀分析反應產物之酯類成分。
本研究分析結果顯示微藻脂質萃取物FAME含量達76.58%，而one-step反應產物FAME含量高達94.71%。在批次實驗中發現鹼性環境會脂肪含量下降，pH7為最佳培養酸鹼值，藻密度為1,136.67 mg/L，最大之生長速率為13.2 day-1，總脂質含量達乾重之25.5％。2,930 lux為最佳光照條件，累積之藻密度為770 mg/L，最大之生長速率為8.26 day-1，總脂質含量為乾重之32.03％。高光照培養會使此藻種累積藻細胞質量，但是在9,600 lux培養時會使藻細胞產生光抑制作用，使葉綠素含量下降。而15％CO2之曝氣濃度藻密度累積量最大能達到1,288.33 mg/L，最大生長速率為12.75 day-1，脂質累積量以30％CO2曝氣濃度培養時脂質含量達乾重之45.68％為最高。由批次實驗Chlorella vulgaris生長以及脂質累積結果中，本研究選定pH7、2,930 lux以及30％CO2曝氣濃度做為最適合之連續式培養條件。

關鍵字

二氧化碳 ； 光照強度 ； 酸鹼值 ； Chlorella vulgaris

並列摘要

Recently the researches on the CO2 fixation have been focused on the biological utilization. Microalgae will be able to use the carbon dioxide as a carbon source, produced high-density biomass, and the single cell oil extracted from biomass can be transformed into biodiesel.
This study used the high lipid content of green algae Chlorella vulgaris as the research object. Firstly, we used continuous culture to enlarge algae. Then, we set several batch experiments to control different pH, illumination and the aeration with different concentration of carbon dioxide. Through comparison of chlorophyll a, optical density, MLSS, cell number and lipid content to discuss the growth situation, we selected the most suitable condition for the growth of this algal species. We chose one-step method, which is a single-step transesterification reaction, to convert fatty acids into fatty acid methyl esters（FAME）, and then using gas chromatography (GC) to analysis esters of reaction products.
Results showed that the ratio of FAME in the extract of microalgae lipid was 76.58%, while after the one-step reaction, the ratio of FAME could raise to 94.71%. Results of batch experiment showed that alkaline environment decreased lipid content, and pH 7 was the best culture condition with algae density of 1,136.67 mg/L, growth rate of 13.2 day-1 and the total lipid content of 25.5% dry weight. The best illumination condition is 2,930 lux with accumulation of algal density of 770 mg/L, growth rate of 8.26 day-1 and total lipid content of 32.03% dry weight. It was found out that culture in high-light can accumulate the biomass of algal cells. However, growth of algae was inhibited when cultured in the 9,600 lux, and content of chlorophyll a was decreased. In CO2 batch experiments, MLSS can be accumulated up to 1,288.33 mg/L under 15% CO2 concentration of the aeration, while the maximum growth rate was 12.75 day-1. In addition, lipid accumulation the highest lipid content was 45.68% dry weight under 30% CO2 concentration of the aeration. Through batch experiments and results of lipid accumulation, this study selected pH 7, 2,930 lux, and 30% CO2 concentration as the optimal conditions for continuous culture.

並列關鍵字

Chlorella vulgaris ； illumination ； CO2 ； pH

參考文獻

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