Search

In order to obtain microorganisms that can synthesize of oxo cyclic amino acids from hydroxy cyclic amino acids, we performed screening of microorganisms that are able to do so from 10 microbial samples collected from the Kyoto University Botanical Garden. Isolated microorganism colonies were shake-incubated in a liquid nutrient medium containing hydroxy cyclic amino acids as the only source of carbon, and the resulting suspension was subjected to TLC analysis with ninhydrin detection. According to the analysis, hydroxy cyclic amino acids in the liquid medium were decomposed by the microorganisms; however, oxo cyclic amino acids could not be detected. The resting microbial reaction of the isolated colonies was also performed, but the same results were obtained. Therefore, we isolated microorganisms that utilize hydroxy cyclic amino acids from the environment during single carbon source?medium cultivation, but were unable to isolate any microorganisms able to produce oxo cyclic amino acids from hydroxy cyclic amino acids. 医薬品の出発素材であるオキソ環状アミノ酸の化学合成にはコストがかかり，環境負荷も大きい．そこで，水酸化環状アミノ酸を基質とする温和かつ安価なオキソ環状アミノ酸の微生物変換を目指し，環境中の有用微生物の探索を行った．まず，水酸化環状アミノ酸資化性菌の入手を目的として，京大理学部植物園から10 個の微生物分離源を採取，水酸化環状アミノ酸を単一炭素源とする液体培地で20℃，2 週間の振とう培養を行った．黄濁が認められた培養液をTLC 分析に供したところ，基質となる水酸化環状アミノ酸の消失が観察された．そこで，培養液中の微生物を同一組成の寒天培地上で分離し，得られた各水酸化環状アミノ酸資化性菌を水酸化環状アミノ酸を基質とする最小栄養液体培地での振とう培養と休止菌体反応に供した．TLC 分析の結果，両溶液中で水酸化環状アミノ酸の消費が認められたものの，目的物であるオキソ環状アミノ酸は検出されなかった

Sebacic acid, a monomer of nylon, is a promising carbon-neutral monomer because it is made from castor oil. Castor oil is an inedible vegetable oil that is rich in ricinoleic acid. However, the production of sebacic acid requires a large input of energy due to the need for high pressure and high temperature, as well as highly alkaline reaction conditions. Therefore, we applied microbial technology in an attempt to develop an eco-friendly sebacic acid production process. We collected microbial samples from the Kyoto University Botanical Gardens. These samples were inoculated into medium containing castor oil, following which, we performed subculturing. After isolating pure cultures of several kinds of microorganisms, we performed TLC and GC analysis. According to our TLC analysis, almost all the microbial isolates were able to degrade castor oil. Despite this, our GC analysis indicated that none of the isolated microorganisms were able to produce sebacic acid. ナイロン原料のセバシン酸は非可食性植物油であり，リシノール酸を豊富に含むヒマシ油から作られている．しかしそのプロセスは高アルカリ条件下で高温・高圧を必要とするため，環境負荷が高いという問題がある．そこで微生物のバイオテクノロジーを利用し，温和な条件でリシノール酸からセバシン酸を生産することを目的に研究を行った．京都大学理学部植物園でサンプリングを行い，ヒマシ油を基質とした最少栄養培地で植菌を行った．その後植え継ぎを行い，画線による分離，単離後，TLC とGC による脂質組成の分析を行った．単離した結果，16 種類のバクテリアやカビを得た．TLC 分析の結果，ほとんどのサンプルにおいてヒマシ油が分解されていることが分かった．GC 分析の結果，セバシン酸を生産している微生物は得られなかった．

Plastic is an essential material in modern day society. Most plastics are produced by a chemical process using petroleum. Plastic production thus cannot be said to be either resource- or environmentally friendly. Therefore, in recent years, research has been conducted into bioprocess production of plastics by using a microbial enzyme. In this study, we attempted to identify microorganisms that catalyze the decarboxylation of dicarboxylic acid to produce a carboxylic acid, which is the raw material for plastic production. Our ultimate aim was to identify microorganisms capable of fermentative production of carboxylic acids from biomass. Although we isolated a large number of bacteria using the dicarboxylate medium, we did not manage to identify any microorganisms that catalyze decarboxylation of dicarboxylic acid. We believe that the microorganisms we isolated may be heterotrophic, and any decarboxylase activity against dicarboxylic acid is very weak. Alternatively, they may be autotrophic and capture carbon dioxide in the air as a carbon source without assimilating the substrates. To distinguish between the two possibilities, it is necessary to screen more samples. プラスチックは現代社会を支える重要な素材であるが，これらの多くは石油を使用した化学プロセスによって生産されている．しかし，このプロセスは資源環境の面で好ましい生産法とは言えない．そのため，近年では，微生物酵素を用いたバイオプロセスによる生産が進められている．そこで，バイオマスによる発酵生産が可能なジカルボン酸を脱炭酸反応させ，プラスチックの原料となるカルボン酸を生成する反応を触媒する微生物の発見を最終目標として研究を行った．結果は，培地上には多数の菌が見られたが，TLC分析では，今回サンプリングしたサンプル中にはジカルボン酸の脱炭酸反応を触媒する微生物は見つからなかった．ここから，得られた菌が従属栄養生物であり，基質に対する活性が非常に弱いこと，または独立栄養生物であり，基質を資化せずに空気中の二酸化炭素を炭素源として取り込んでいることなどが考えられる．