In a dry 500 mL culture shake flask with baffles, 2-oxononon-8-enoic acid (6, 2.54 g, 0.0149 mol, 1.0 equiv), D-glucose (2.75 g, 0.01531 mol, 1.03 equiv), nicotinamide adenine dinucleotide (NAD, 0.103 g, 0.00016 mol, 0.0107 equiv) and glucose dehydrogenase (GDH-105, 0.075 g; or any equivalent of GDH) were suspended in 142 mL of 2 M ammonium chloride and ammonium hydroxide buffer solution (pH 9.5). To this mixture, add a solution of leucine dehydrogenase (LeuDH) precipitate (original culture volume: 75 mL) suspended in 7.5 mL of Bacterial Protein Extraction Reagent (BPER). (Alternatively, LeuDH particles can be cleaved by sonication). The final reaction volume was 150 mL at pH 9.0. the mixture was stirred at 37°C on an oscillator. The progress of the reaction was monitored by HPLC and the reaction was considered complete after 24 hours. The post-reaction processing procedure was as follows: the enzymatic reaction mixture was diluted with chloroform (100 mL) and the mixture was stirred at ambient temperature (19-23 °C) for 1 h, followed by standing overnight.After 12 h, the bottom organic phase was separated from the upper aqueous phase containing solids, and the aqueous phase was filtered as a suspension under vacuum using a 13 cm Büchner funnel and Whatman No. 1 filter paper. The wet filter cake was washed with chloroform (1 x 20 mL) and dried under vacuum at 23 °C for 14 hours. 1.93 g of (S)-2-aminonon-8-enoic acid (2) was obtained as a colorless solid in 87.3% yield and >99% enantiomeric excess.
