小球藻在氯化鈉與氮源調控下油脂與碳水化合物變化之研究

The study of NaCl and nitrogen concentration on lipid and carbohydrates content in Chlorella

洪子剛(tzu-kang Hung)

指導教授 ： 黃郁慈

中原大學/工學院/生物環境工程研究所/碩士(2015年)

https://doi.org/10.6840/cycu201500824

摘要

隨著石油日漸減少，需尋找替代能源，目前四大能源有: 煤、石油、天然氣、生質能，其中只有生質能為可再生能源，因此開發生質能源為各國致力研究項目之一，而微藻為其中一種生質原料，與其他生質作物相比，具有生長快速、油脂含量高、固碳能力。
本研究使用Chlorella sp.作為實驗藻株，經純化並篩選後，具生長快速與高油脂之微藻S-A，將S-A以兩階段加氯化鈉培養，研究藻油與碳水化合物在調控氮源與氯化鈉下之產率變化情形，第一階段使用調控氮源之合成廢水培養基，氮源濃度分別調整為40、177、300 mg/L，培養至第六天時進入第二階段，加入濃度分別為0、10、20 g/L氯化鈉。每天測量吸光值、細胞數、乾重做為分析數據，且在第二階段培養12、24 hr之後，測量油脂與碳水化合物含量。應用以上數據以反應曲面法分析，取得油脂與碳水化合物之最佳生產條件，提供未來研究生質能原料與生產之條件。
本研究使用微藻S-A在起始氮源177 mg/L之下，於第二階段加入10 g/L氯化鈉時，有最高的油脂產率75.9 mg/L/day；而S-A以起始氮源300 mg/L培養，有最高之碳水化合物產率47.9 mg/L/day。實驗結果顯示微藻S-A於適當的鹽度下，可提高微藻油脂含量與藻油產率，但是鹽度不利於碳水化合物的累積。最後將實驗之數據以反應曲面法之多項式回歸方程式取得生質能原料之最佳解，油脂產率之最佳解: NO- 3= 195 mg/L；NaCl= 4.9 g/L，碳水化合物產率之最佳解: NO- 3= 279.6 mg/L；NaCl= 0.17 g/L，依據生質能原料的不同，可依照本研究之結果調整培養參數以達到最大效益。

關鍵字

微藻 ； 氮源 ； 氯化鈉 ； 生質能源

並列摘要

In recent years, fossil fuels are gradually depleted due to massive developments of the industry. Therefore, we need to search alternative energy sources. Today, there are four major energy resources: coal, fossil oil, natural gas, and biomass energy. In this situation, biomass energy is the only renewable resource that makes it a great subject to solve the problem of energy shortage. In different kinds of biomass energy resources, microalgae are regarded as the feedstock of sustainable biodiesel because of their higher lipid contents, faster growth and carbon fixing rates compared to regular terrestrial plants which have been used to produce biomass energy.
In this study, Chlorella sp. S-A of faster growth rate and higher oil content among candidates were selected and cultivated in a two-stage procedure. Three different concentrations of nitrogen and NaCl supplements were treated, and investigated their effects on lipid and carbohydrate productivities in Chlorella sp. S-A. The first stage was designed to optimize biomass productivity by using modified artificial wastewater in which nitrogen concentrations were adjusted to 40, 177, 300 mg/L, respectively. After 6 days, system was shifted to the second stage. In the second stage, we added NaCl and adjust concentrations to 0, 10, 20 g/L, respectively. The optical density, cell numbers and dry weights were measured daily. After 12 and 24 hours of culturing, we harvested algae for measuring the oil and carbohydrate contents. By using response phase method to analyze the data, we got the best conditions for accumulating oil and carbohydrates, and the results may provide optimum information of bioenergy productions.
The highest oil productivity (75.9 mg/L/day) was obtained at the initial nitrogen feed of 177 mg/L NO- 3, and 10 g/L NaCl at the later stage. The highest carbohydrates productivity (47.9 mg/L/day) was obtained at the initial nitrogen feed of 300 mg/L NO- 3. These results indicated that culturing algae S-A under appropriate salinity can increase oil content and productivity, but concentration of NaCl was not related to the accumulation of carbohydrates. The experimental data applied in the polynomial regression equation of response surface methodology was used to obtain the best solution of bioenergy raw materials. The best solution of oil productivity was 195 mg/L NO- 3 and 4.9 g/L NaCl. The best solution of carbohydrate productivity was 279.6 mg/L NO- 3 and 0.17 g/L NaCl. To achieve the maximum bioenergy production efficiency from different feedstock, culturing parameters may be adjusted according to the results of this study.

並列關鍵字

microalgae ； nitrogen ； sodium chloride ； bioenergy

參考文獻

蘇純平，2010，微藻類之生質能源開發，中原大學土木工程學系碩士論文。

張哲瑋，2012，不同條件下對小球藻生長與油脂累積之探討，中原大學土木工程學系碩士論文。

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