作物栽培之雜草管理大都以施用化學除草劑為主，為維護農業生態系的永續發展及人畜安全，生物除草劑 (bioherbicides) 的開發成為漸受關注的課題。生物感測器為一種分析裝置，主要聯結生物性感應元件及訊息轉換元件所組成，具有操作簡易、快速及靈敏等特性。本研究建構轉殖大腸桿菌(Escherichia coli)為感測器，以阿拉伯芥(Arabidopsis thaliana (L.) Heynh) 胱硫醚-β 分解酶 (cystathionine β-lyase, CBL)及乙酮醇酸還原異構酶 (ketol-acid reductoisomerase, KARI)為感測之標的酵素，篩選可抑制CBL 或KARI 酵素活性而具防除雜草潛力之鏈黴菌發酵液。阿拉伯芥CBL 與 KARI cDNA 全長分別為 1,395 bps 與1,776 bps，構築在pET-28a(+) 載體後，轉形於大腸桿菌 BL21(DE3) pLysS 菌株，經 1 mM IPTG 誘導，可分別大量表現約 46 及57 KDa 之CBL 及 KARI 重組蛋白，再以aminoethoxyvinyl glycine (AVG) 與 cyclopropane-1,1-dicarboxylic acid (CPD) 抑制劑建立檢量線。檢測之微生物資材為自行採集、分離及鑑定之鏈黴菌屬菌株(Streptomyces sp.)，經固態培養及簡易發酵後，將發酵液添加於含阿拉伯芥 CBL 及KARI 之重組大腸桿菌菌液中，1 小時內即可檢出鏈黴菌S7 鏈黴菌株發酵液，具有抑制KARI 活性之潛力。本研究建構植物特定酵素活性的快速感測平台，不僅有助於微生物代謝物作用機制的闡明，亦有利於篩選低動物毒性的生物性資材。

Chemical herbicides are mostly used in weed management in crop cultivation. In order to achieve the sustainable development of agro-ecosystems as well as human and animal health, biological herbicide (bioherbicides) development has become the current topic of concern. Biosensor is an analytical device which combines biological detector element and signal processors, with simple operation, rapid and sensitive characteristics. In the present work, we construct the recombinant cystathionine-β enzyme (cystathionine β-lyase, CBL) and ethyl ketone alkyed isomeroreductase (ketol-acid reductoisomerase, KARI) from Arabidopsis thaliana (L.) Heynh in Escherichia coli. The whole cells are sensing system for screening microbial materials for potential bioherbicides by enzymatic inhibition assay of CBL or KARI. In addition, we have isolated and characterized the full length cDNAs of CBL and KARI with 1395 and 1776 bps, respectively. The target genes were cloned into the pET-28a(+) vector and transformed into E. coli BL21(DE3) pLysS strain. The expression of recombinant proteins was induced by the addition of 1 mM IPTG. The CBL and KARI genes encode proteins of molecular weight 46 and 57 KDa, respectively. Here we report several isolated Streptomyces sp. strain, and the metabolites was produced by solid state culture and simple fermentation. The products was harvested by centrifugation then screened by this sensor system. The Streptomyces sp S7 was assayed within one hour, employing a calibration curve established with various concentrations of aminoethoxyvinyl glycine(AVG) or cyclopropane-1, 1-dicarboxylic acid (CPD). In this study, we have developed a fast system detecting inhibitory activity of a specific plant enzyme. This system can not only be applied to elucidate microbial metabolites mechanisms, but also to screen biological materials of low animal toxicity.