A Japanese screening approach: Selection of an opine dehydrogenase and alkaline D-Peptidase

This chapter examines a Japanese screening approach, which includes selection of opine dehydrogenase and alkaline D-peptidase. It introduces enrichment and acclimation techniques with the isolation of nitrile degraders as typical examples. Enrichment culture technique is a method to isolate microorganisms having a specific ability to grow on a medium which has a specified feature in its composition and conditions, such as carbon and nitrogen sources, pH, temperature, and aeration. Microorganisms growing faster than the other species become dominant in the culture. Acclimation technique is run with a toxic or unnatural compound as a substrate and usually with a longer term to isolate microorganisms which are not easily isolated by the enrichment culture technique. Opine-type secondary amine dicarboxylic acids are useful chiral intermediates of angiotensin-converting enzyme (ACE)-inhibitors, such as enalapril and lysinopril. A novel NAD+-dependent opine dehydrogenase is purified to homogeneity from Arthrobacter sp. strain 1C isolated from soil by an enrichment culture technique with a synthetic substrate N-[1-DL-(carboxyl)ethyl]-L-phenylalanine.