探討界面活性劑在Phanerochaete chrysosporium水解木質纖維素的效益

Effect of surfactants on the hydrolysis of lignocellulose by using Phanerochaete chrysosporium

劉于萱(Yu-Hsuan Liu)

指導教授 ： 蘇文達

國立臺北科技大學/工程學院/化學工程研究所/碩士(2010年)

摘要

生質能源為現今全世界最矚目的話題，木質纖維素是未來可以進一步開發生質能源的新興原料，台灣每年經由稻草、甘蔗渣及果菜加工工廠所生產的農業廢棄物有600萬噸。
本研究先以稻稈或甘蔗渣為基質，分別使用二次去離子水或酸及鹼處理再加上高溫高壓裂解作為前處理，並選用擔子菌類Aspergillus niger 和Phanerochaete chrysosporium作為後期培養菌種。初步發現，稻稈經二次去離子水加上高溫高壓裂解處理後，接著將P. chrysosporium和A. niger菌種於37 ℃、130 rpm、pH 4下，以不同混合比例做液態培養，結果顯示，單獨P. chrysosporium菌種在120小時培養後可產生105.23 U/mL之endo-β-1,4-D-glucanase活性、10.24 U/mL之β-1,4-D-glucosidase活性與1.77 mg/ml之還原糖，其酵素活性與水解糖化能力優於不同比例菌種混合培養。
另外，界面活性劑可以增加酵素穩定性，並且能促進纖維素水解成還原糖，因此，以不同種類的界面活性劑 (例如化學合成界面活性劑或是生物界面活性劑) 添加到培養基中，探討界面活性劑對酵素性水解纖維素的效益。以稻桿為基質液態培養P. chrysosporium菌種，在48小時前培養後，分別添加0.025 %非離子型與陰離子型化學界面活性劑 (例如Tween 80, Triton X-100, Span 60, PEG 4000, Sodium Dodecylbenzene Sulfonate, Sodium Laurylsulfate, Sodium Lauroyl Glutamate)到培養基中。結果發現，添加SDBS陰離子型界面活性劑在96小時培養後，酵素活性、還原糖產量會被抑制，但添加0.00625 % PEG 4000非離子型界面活性劑經96小時培養，endo-β-1,4-D-glucanase、β-1,4-D-glucosidase、cellulase酵素活性與還原糖分別為165.57 U/mL、40.58 U/mL、0.50 U/mL與3.03 mg/mL，比沒有加入界面活性劑時分別高出2.05倍、4.52倍、3.13倍與2.05倍。由此可知，在酵素水解纖維素的過程中，添加PEG 4000非離子型界面活性劑可使酵素活性提高並增加還原糖的產量。

關鍵字

Phanerochaete chrysosporium ； endo-β-1,4-D-glucanase ； β-1,4-D-glucosidase ； 界面活性劑 ； 木質纖維素

並列摘要

Biomass energy is one of the most prominent topics in the world today. Lignocellulose is a suitable and noticeable raw material for further development in future. There are six million tons of agricultural waste produced every year in Taiwan, such as rice straw, sugarcane bagasse, waste of fruit and vegetable processing plants.
In this study, we used rice straw and sugarcane bagasse as a substrate, and mixed with deionized water or acid and alkali, then followed with high pressure and temperature decomposition. We utilized basidomycetes, including Aspergillus niger and Phanerochaete chrysosporium with different ratio with pretreated substrate for liquid culture under pH 4, 37℃ and 130 rpm. The results showed that P. chrysosporium strains alone could produce 105.23 U/mL activity of the endo-β-1,4-D-glucanase, 10.24 U/mL activity of β-1,4-D-glucosidase and 1.77 mg/mL of reducing sugar for 120 hours cultivation. This result is better than the two strains coculture in different proportional mixing.
In addition, surfactants could increase enzyme stability and enhance the enzymatic conversion of cellulose to reducing sugars. Therefore, we add different types of surfactants, such as chemical surfactant or biosurfactant into the medium to explore the effect of surfactant in the lignocelluloses hydrolysis. We seeded P. chrysosporium to rice straw substrate for 48 h liquid culture, then added 0.025 % non-ionic or anionic surfactants, including Tween 80, Triton X-100, Span 60, Polyethylene Glycol 4000, Sodium Dodecylbenzene Sulfonate, Sodium Laurylsulfate and Sodium Lauroyl Glutamate, in the medium for continuing to 96 hours. Experimental results showed that anionic surfactant SDBS had negative effect in promoting activity of enzyme and reducing sugar production for 96 hours culture. However added 0.025 % non-ionic surfactant PEG 4000, it can produce endo-β-1,4-D-glucanase 165.57 U/mL, β-1,4-D-glucosidase 40.58 U/mL, cellulase 0.50 FPU/mL and 3.03 mg/mL reducing sugar, respectively. That increased 2.05 times, 4.52 times, 3.13 times and 2.05 times compared with no added surfactant. Based results, PEG 4000 non-ionic surfactant could increase enzymatic activity and reducing sugar yield in the lignocelluloses hydrolysis process.

並列關鍵字

Phanerochaete chrysosporium ； endo-β-1,4-D-glucanase ； β-1,4-D-glucosidase ； surfactants ； lignocellulose

參考文獻

[1] 張嘉修、陳幸德、黃怡倩、羅泳中，纖維素料原技術之研發概況與展望，國立成功大學化工系，化工期刊，No.54(1)：107-133 (2007)。

[5] 陳文恆、郭家倫、黃文松、王嘉寶，纖維酒精技術之發展，植物種苗生技，No.9：62-69 (2007)。

[6] Zhang, Y.-H. Percival. Reviving the carbohydrate economy via multi-product lignocellulose bioreWneries. J Ind Microbiol Biotechnol. 35: 367–375 (2008).

[7] McMillan J. D. Biotechnological routes to biomass conversion. National Bioenergy Center, NREL (2004).

[9] Zhang, Y.H.P., Lynd, L.R. Toward an aggregated understanding of enzymatic hydrolysis of cellulose: Noncomplexed cellulase systems. Biotechnology and Bioengineering. 88: 797-824 (2004).