Continuous ethanol fermentation using immobilized yeast cells

Abstract

Growing cells of Saccharomyces cerevisiae immobilized in calcium alginate gel beads were employed in fluidizedbed reactors for continuous ethanol fermentation from cane molasses and other sugar sources. Some improvements were made in order to avoid microbial contamination and keep cell viability for stable long run operations. Notably, entrapment of sterol and unsaturated fatty acid into immobilized gel beads enhanced ethanol productivity more than 50 g ethanol/L gel h and prolonged life stability for more than one-half year. Cell concentration in the carrier was estimated over 250 g dry cell/L gel. A pilot plant with a total column volume of 4 kL was constructed and has been operated since 1982. As a result, it was confirmed that 8-10%(v/v)ethanol-containing broth was continuously produced from nonsterilized diluted cane molasses for over one-half year. The productivity of ethanol was calculated as 0.6 kL ethanol/kL reactor volume day with a 95% conversion yield versus the maximum theoretical yield for the case of 8.5% (v/v) ethanol broth.

Ion-implanted polytetrafluoroethylene enhances Saccharomyces cerevisiae biofilm formation for improved immobilization

“…Encapsulation in polymer-gel showed a good yield of ethanol. Nagashima et al [9] reported pilot plant operations with yeast cells immobilized in calcium alginate for 4000 h with a productivity of 2.4 kl ethanol per day. The disadvantages of this and other encapsulation methods arise from the need for nutrients to diffuse into the gel and for ethanol and CO 2 to diffuse out of the gel, frequently causing damage to the gel and cell loss [12].…”

Diluted Acid Pretreatment of Pinus Radiata for Bioethanol Production Using Immobilized Saccharomyces Cerevisiae Ir2-9 in a Simultaneous Saccharification and Fermentation Process

“…It was observed that Eudragit RL 100 (a copolymer of acrylic resin) coating of cell entrapped in alginate beads resulted in 15% higher diffusion of substrate and the leakage of cells was considerably reduced. Nagashima et al 22 operated a pilot plant of 40,000 L capacity, using alginate-entrapped cells of yeast for alcohol fermentation for a period of 4000 h with a constant alcohol production rate of 8.5 to 9.0% by volume. Using Ca-alginate-entrapped cells of S. cereviceae, Iamuna and Ramakrishna 23 reported rapid fermentation of high concentration sugar solution, thereby obtaining 20% (w/v) alcohol in 30 h.…”

Immobilization of Yeast Pichia stipitis for Ethanol Production

“…효모를 고정화하여 ethanol 생산에 이용하는 방법은 여러 문헌에서 보고되고 있으며, 효모 세포 고정화를 통하여 생산 성 향상과 같은 공정상의 여러가지 잇점을 얻을 수 있었다 [12][13][14]20,22]. 그리고, 이러한 고정화 효모 세포를 이용하는 다 양한 반응기 시스템이 연구되어 왔으며 [2,3,[8][9][10]14,26], 특히, 경제성을 고려하여 세포의 흡착을 이용한 다양한 부산물 [2,3,5,9,13,17,18,26]이 세포 고정화를 위한 담체로서 관심을 끌 고 있다.…”

“…그리고, 이러한 고정화 효모 세포를 이용하는 다 양한 반응기 시스템이 연구되어 왔으며 [2,3,[8][9][10]14,26], 특히, 경제성을 고려하여 세포의 흡착을 이용한 다양한 부산물 [2,3,5,9,13,17,18,26]이 세포 고정화를 위한 담체로서 관심을 끌 고 있다. 그 중에서 woodchips, sugarcane bagasse, sorghum bagasse, 그리고 corncob과 같은 agricultural byproducts가 특 히 이러한 경제성과 간편한 방법 때문에 많이 연구되어왔다.…”