光合菌在光生物反應器產氫之研究; Photosynthetic bacteria photobioreactor for H2 production

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Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/3479

Title:	光合菌在光生物反應器產氫之研究;Photosynthetic bacteria photobioreactor for H2 production
Authors:	張志強;Chih-Chiang Chaung
Contributors:	化學工程與材料工程研究所
Keywords:	紫色非硫菌;照光式反應器;氫氣;光合細菌;細胞固定化;photobioreactor;hydrogen;Photosynthetic bacteria;purple non-sulfur PSB;cell immobilization
Date:	2000-07-14
Issue Date:	2009-09-21 12:16:53 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	氫氣是替代石化燃料的最好選擇。由於氫氣燃燒後的產物是水，不會造成環境的負荷，可謂是最乾淨的燃料。因此，氫氣被科學家認為是取代石油世紀的主要能源。目前使用氫氣的的主要瓶頸是缺乏重要相關科技之研發，如良好的生產技術、儲存、運輸與應用科技。在不同生產氫氣的方式以利用太陽能最吸引人且符合永續發展精神的方法。科學家在文獻中也強調生物法生產氫氣較物理法和化學法為優。並且又指出在所有已知之生物系統中，光合菌是最有效率之氫氣生產者。光合菌中的紫色非硫菌，雖然有非常複雜的生理特性，但是有不少菌株具有氫氣之生產能力，並且產量高又穩定，具實用潛力。但是，當應用時發現一個普遍存在的問題，即氫氣生產力的不穩定性;光合菌之氫氣生產力無法在光反應器內持續存在。到目前為止，僅有少數理論對其氫氣生產力不穩定性提出解釋。因此，藉工程的角度來增加其穩定性是必要的。目前解決方法之一是藉細胞固定化來達到氫氣之穩定生產。但是文獻中主要採用之細胞固定化法是膠體包埋法，此法在產程放大(scale-up)時容易受到膠體本身之物性上的限制。有鑑於此，本研究針對未來以生物法進行工業化生產氫氣時，可能面臨之問題，來改進現有光生物反應器之設計。即開發比膠體包埋法成本較低的細胞固定化法--吸附法。本實驗研究成果主要分下列四部分來討論。第一部分是菌種採購與分離篩選; 第二部分是生物反應器之設計與製作; 第三部分是無固定化下，菌種生長特定之探討; 第四部分是在固定化生物反應器中觀察氫氣生產效果。實驗結果顯示，可知不同的照光強度和方式可提高Rhodobacter sphaeroide CCRC13100的生長速率(µ)單面照光為µ=0.019 hr-1，四面照光為µ=0.056 hr-1。對於提高產氫的能力單面照光為qH2=0.653 ml/hr/g cell，四面照光為qH2=1.785 ml/hr/g cell。在Fed-batch連續進料方面，能延長產氫時間和增加產氫量到456 hr並且增加產氫量到298ml/L H2。對於提高產氫的能力可提升到qH2=1.231 ml/hr/g cell。另外，在Fed-batch固定化連續進料方面，能延長產氫時間和增加產氫量以提高產氫能力到1239 hr並且增加產氫量到2690 ml/L H2。對於提高產氫的能力可提升到qH2=2.4 ml/hr/g cell。 Hydrogen is considered to be one of the best alternative fuels to petroleum. Most of pollutants of our environment are resulted from widely using petroleum as fuels. Hydrogen is also the cleanest energy because its product is water after burning with oxygen. It is believed that hydrogen will replace the petroleum as the major fuel in the next era. Scientists have found many different approaches in hydrogen production since the last two decades.Among these approaches, it is believed that utilizing the solar energy to hydrogen production is the most appealing concept.Three methods including chemical, physical, and biological approaches can utilize solar energy for hydrogen production. Biological approach is considered to be better than the other two methods. Among all known biological system, photosynthetic bacteria (PSB) is the most efficient hydrogen producer. PSB can utilize the solar energy for carbon dioxide fixation and hydrogen production. Several purple non-sulfur PSB have been reported to be the best hydrogen producers. One of the common problems using PSB for hydrogen production is the instability of hydrogen producing capability of PSB. There is limited understanding of the instability in the academia. Thus, one common solution to this instability is by gel immobilization. Although gel immobilization can solve the instability problems, it creates other problems such as substrate diffusion difficulty, shading effects from immobilized cells, and scale-up problems. Thus, the major focus of this project is to study the feasibility of using alternative immobilization method – adsorption on cotton fiber for hydrogen production and carbon dioxide fixation. Adsorption immobilization as compared with gel immobilization is considered to be most suitable for large-scale production due to its less mass transfer difficulty and lower operational cost. Thus, higher hydrogen production is expected. Experimental results of this project are presented in four sections: four PSB strains are collected and isolated, design and manufacture of photobioreactors, characterization of PSB by batch fermentation, and performance of immobilized photobioreactors.Experimental data indicated that both reactor design and environmental conditions such as medium composition and light intensity play important role in carbon dioxide fixation and hydrogen production.
Appears in Collections:	[National Central University Department of Chemical & Materials Engineering] Electronic Thesis & Dissertation

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