海洋生物資源を利用した新エネルギーの開発

摘要

海洋は，地球の表面積の約7割を占め，平均深度3800mと陸上と比較してはるかに大きな容積を有する。そこには熱水噴出孔や寒冷な極地，高水庄の深海など様々な環境に適応した多種多様な能力を持った生物が存在する。このことは，生命の誕生の場である海洋において生物史の9割近くが繰り広げられ，生物が様々なエネルギー代謝を獲得してきたことに関係している。生物がエネルギー代謝として酸素発生を伴う光合成を獲得したのは約27億年前である。%The marine environment is remarkably diverse and harbors a wide variety of organisms that have acquired novel metabolic functions and corresponding genes through evolutionary adaptation. Marine organisms are potentially a treasure of gene resources. Especially, much attention has been paid to photosynthetic organisms because they can grow with inorganic carbon fixation, produce useful materials and convert photo-energy into bio-fuel. On the other hand, it is known that standard culturing techniques account for only 1 % or less of the bacterial diversity in the environments. Therefore, recently, marine metagenomic approach with construction of genomic libraries by direct extraction and cloning of DNA from environmental samples has been applied to analyze and utilize the unculturable microbes as gene resources. Furthermore, it has also become important tool for screening useful enzyme genes in biofuel production.