使用Clostridium butyricum自含酚廢水中產氫

Abstract

本研究著重於使用Clostridium butyricum自含酚廢水中產氫。使用葡萄糖 (glucose) 和纖維二糖 (cellobiose) 為合成廢水中之主要碳源並且觀察其在含酚廢水中對於酚的耐受性和產氫能力。 在批次實驗中，發現C.butyricum在毒性環境中也能夠產生氫氣。氫氣產率對於以葡萄糖和纖維二糖為碳源分別為1.46 mole H2/mole glucose和2.11 mole H2/mole cellobiose而且在糖類發酵降解的過程中也觀察到酚有被降解掉。 在以cellobiose為碳源的批次實驗中發現最高的氫氣產率是發生在酚濃度為600 ppm的時候而不是無酚的環境，而漆氧化酶 (laccase) 的活性分佈與氫氣產率相同，在600 ppm時候最高，由於酚被漆氧化酶轉化成丙酮酸 (pyruvate) ，其在繼續被CoA轉化成acetyl-CoA時會釋放出氫氣，而較多的酚被轉化則在變成acetyl-CoA的過程中有較多的氫氣被釋放，這或許說明了所以在600 ppm時候氫氣產率最高的原因。而漆氧化酶的活性隨著酚濃度的更提高由於毒性對於C.butyricm的抑制造成活性開始下降。氫化酵素活性則是隨著酚濃度的提高而減少，在無酚濃度時的活性是最高的，但是若在培養液中有酚的存在則減少，在全部的產氫速度與氫化酵素的產速度中有一段差距，這段可能是由細胞膜上的氫化酵素 (membrane-bound hydrogenase) 所作用，而當酚濃度的提高，因為毒性對C.butyricum的抑制所以膜上的氫化酵素活性反而漸漸減少。

This thesis focus on the research of producing hydrogen in phenol-containing synthetic wastewater using Clostridium butyricum which has very good ability of hydrogen production by degrading hydrocarbons. And we use glucose and cellobiose as the main carbon source its concentration to culture and observe its resistance to phenol and ability of hydrogen production. During batch experiment, we discover C.butyricum had bood performace of hydrogen production in toxic surrounding. The highest hydrogen production of C.butyricum is 1.46 mole hydrogen．mole-1 glucose and 2.11 mole hydrogen．mole-1 cellobiose when using glucose and cellobiose as main carbon source. We also found phenol was degraded during glucose and cellobiose fermentation. In cellobiose fermentation batch test, we found C.butyricum can produce higher hydrogen yield in phenol-containing medium than no phenol and the highest hydrogen yield is 2.11 at 600 ppm. The activity of laccase also was highest at 600 ppm. Maybe more phenol was cracked and converted to pyruvate by laccase and pyruvate was converted to acetyl-CoA and released hydrogen. Therefore more hydrogen was produced at 600 ppm phenol concentration. As the phenol concentration over 600 ppm the hydrogen yield began to decrease because high phenol concentration inhibit C.butyricum growth. Hydrogenase activity was decrease as phenol concentration increase. The activity of ydrogenase was highest when no phenol inside and cut down immediately in the presence of phenol. But it had a gap between overall hydrogen production rate and enzymatic hydrogen production rate. The difference maybe from membrane-bound hydrogenase. Membrane-bound hydrogenase activity was low gradually because the inhibition of phenol.