해조류를 이용한 바이오연료 기술 현황 및 전망

다국어 초록 (Multilingual Abstract)

Current commercialized Bioethanol feedstocks, with the exception of woody feedstock, are biomass that have a direct effect on the world’s food supply. As such, there are moral issues at hand as well as the question of if there will be enough supply to meet the rising energy demands. In addition, mass farming of corn, the current leading feedstock in world ethanol production, uses significant amounts of pesticides and nitrogen fertilizers which in turn cause corrosion of arable land. Also, farming of any land based plants cannot avoid the use of fresh water. Stockholm Environment institute warns of serious water scarcity in the near future. Therefore nations like Korea that do not possess enough arable land and biomass need to seek out alternate sources of biomass in order to produce bioenergy in sufficient quantities. The marine environment surrounding the Korean peninsula can be effectively used for both bioenergy production and CO2 reduction. Algae, compared to other biomasses, have a very fast cultivation cycle(In case of tropical climates, it can be harvested 4~6 times annually). They are grown in the vast open sea eliminating the need for dry arable land. In addition they require very little or none of the costly resources that are required to grow other feedstock. (e.g. fresh water, fertilizer etc.) Also, the preparation and saccharification processes are much simpler than that of woody feedstock as algae do not contain lignin. As the total conversion yield is high, if it were to be mass cultivated in Southeast Asia, Bioethanol can be produced from algae at about the same level of process cost as sugar or starch based feedstock. Algae is broadly classified into two categories, macroalgae and microalgae. Macroalgae are further divided into three categories: red algae, brown algae and green algae. Bioethanol production technology with red algae feedstock will be the focus of this article. Bioethanol is gaining attention as one of the foremost bioenergies that can lower crude oil dependence. Some advantages of Bioethanol include ease of transport/ storage/use (compared with gaseous bioenergy) and ease of production (compared with butanol). The main reason why red algae is considered a suitable feedstock for ethanol production is due to its high carbohydrate content. Red algae Bioethanol production process is composed of [Saccharification] － [Fermentation] － [Separation and Refining]. The saccharification or hydrolysis process converts the polysaccharides present in red algae into monosaccharides that can in turn be used by various fermentation agents. The saccharification takes place through the use of enzymatic or acidic means. The saccharification product is then fermented into ethanol using the use of fermentation agents. The fermented ethanol is then separated and refined to yield 99.5% purity fuel grade ethanol. Compared to woody biomass that is mainly composed of lignin, C5 hemicelluose and cellulose, red algae is mainly composed of galactan and cellulose. As such, the costly and troublesome lignin removal process, essential for woody Bioethanol production, is not needed in red algae Bioethanol production. Through these Results, red algae bioethanol production will allow Korea to maintain its status as a producer nation by meeting the CO2 emission regulations set by the Kyoto protocol and further playa major role in allowing Korea to develop into a foreig nenergy independent nation.