Reductive activity of free and immobilized cells of cyanobacteria toward oxophosphonates-comparative study.

This report, based on the previous studies, compares the reductive activity of different modes of following photobiocatalysts (on laboratory and preparative scale): , cf. and , toward diethyl esters of 2-oxopropylphosphonate (1), 2-oxo-2-phenylethylphosphonate (2), and 2-oxobutylphosphonate (3). It was confirmed that immobilization in alginate matrix do not affect the activity and viability of the biocatalysts. Corresponding ()-hydroxyphosphonates (1a-3a) were obtained with similar efficiency compared to the free-cell mode with the yield and of the optical purity respectively (e.g., experiments): (1) yield: 21 %, . 84 %; (2) yield 97 %, . 97; (3) yield 21 %, 89 %. Scaling up the processes for the best biocatalyst, , indicated that the use of free-living cells of cyanobacteria is more effective (640 mg of substrate 2, 44 % of yield, 91 % of ..), compared to the column bioreactor packed with immobilized cells of this photobiocatalyst (384 mg of substrate 2, 38 % of yield, 86 % of ). In the case of free and immobilized cells of cf. , agitation of the medium was the crucial activity mediator. Shaking culture of free cells of cf. converted the diethyl 2-oxo-2-phenylethylphosphonate (2) with the yield of 43 % (99 % of ) compared to 18 % (99 % of , stationary culture). Immobilized cells of this cyanobacterium were also more active toward (2) under shaking conditions (28 % of yield, 99 % of ) than free ones without agitation.