Accumulation mechanism of biofilm under different water shear forces along the networked pipelines in a drip irrigation system.

The behavior of clogging has a close relationship with the biofilm attached on inner surface of the pipeline in a drip irrigation system using reclaimed water. Therefore, inhibiting biofilm growth is the key to completely addressing the clogging problem. Water shear forces play a vital role in the formation, development and detachment of biofilm.

Highly efficient bioreduction of 2-hydroxyacetophenone to (S)- and (R)-1-phenyl-1,2-ethanediol by two substrate tolerance carbonyl reductases with cofactor regeneration.

Optically pure 1-phenyl-1,2-ethanediol is a very important chiral building block and intermediate in fine chemical and pharmaceutical industries. Reduction of 2-hydroxyacetophenone provides a straightforward approach to access these important compounds. In this study, two enantiocomplementary carbonyl reductases, BDHA (2,3-butanediol dehydrogenase from Bacillus subtilis) and GoSCR (polyol dehydrogenase from Gluconobacter oxydans) were discovered for the first time to convert 2-hydroxyacetophenone (2-HAP) to (R)-1-phenyl-1,2-ethanediol ((R)-PED) and (S)-1-phenyl-1,2-ethanediol ((S)-PED) with excellent stereochemical selectivity, respectively.

Conversion of glycerol to 1,3-dihydroxyacetone by glycerol dehydrogenase co-expressed with an NADH oxidase for cofactor regeneration.

Objectives: To investigate the efficiency of a cofactor regeneration enzyme co-expressed with a glycerol dehydrogenase for the production of 1,3-dihydroxyacetone (DHA).

Results: In vitro biotransformation of glycerol was achieved with the cell-free extracts containing recombinant GlyDH (glycerol dehydrogenase from Escherichia coli), LDH (lactate dehydrogenase form Bacillus subtilis) or LpNox1 (NADH oxidase from Lactobacillus pentosus), giving DHA at 1.3 g l(-1) (GlyDH/LDH) and 2.

Cloning and characterization of two distinct water-forming NADH oxidases from Lactobacillus pentosus for the regeneration of NAD.

Two uncharacterized nicotinamide adenine dinucleotide (NADH) oxidases (named as LpNox1, LpNox2) from Lactobacillus pentosus ATCC 8041 were cloned and overexpressed in Escherichia coli BL21 (DE3). The sequence analysis revealed that the two enzymes are water-forming Noxs with 64 % and 52 % identity to LbNox from Lactobacillus brevis DSM 20054. The optimal pH and temperature of the purified LpNox1 and LpNox2 were 7.