An efficient two-step enzymatic process for production of (R)- and (S)-ethyl-3-hydroxybutyrate (HEB), two important chiral intermediates for the pharmaceutical market, was developed and scaled-up to a multikilogram scale. Both enantiomers were obtained at 99% chemical purity and over 96% enantiomeric excess, with a total process yield of 73%. The first reaction involved a solvent-free acetylati...

The in situ regeneration of reduced nicotinamide cofactors (NAD(P)H) is necessary for practical synthesis of many important chemicals. Here, we report the engineering of a highly stable and active mutant phosphite dehydrogenase (12x-A176R PTDH) from Pseudomonas stutzeri and evaluation of its potential as an effective NADPH regeneration system in an enzyme membrane reactor. Two practically impor...

In this study, trypsin (Enzyme Comission 3.4.21.4) was immobilized in a low cost, lignocellulosic support (corn cob powder-CCP) with the goal of obtaining peptides with bioactive potential from cheese whey. The pretreated support was activated with glyoxyl groups, glutaraldehyde and IDA-glyoxyl. The immobilization yields of the derivatives were higher than 83%, and the retention of catalytic ac...

This study aimed to develop an optimal continuous process for lipase immobilization in a bed reactor in order to investigate the possibility of large-scale production. An extracellular lipase of Pseudozyma hubeiensis (strain HB85A) was immobilized by adsorption onto a polystyrene-divinylbenzene support. Furthermore, response surface methodology (RSM) was employed to optimize enzyme immobilizati...

-We have made an experimental study of the isomerization of fructose and glucose by glucose isomerase in two forms: one soluble and the other immobilized by being fixed in a gel matrix. For the latter technique we used a fixed-bed differential reeirculation reactor, which allowed us to obtain comparable results to those we got with the enzyme dissolved within a batch reactor. We propose a simpl...

A cyclic batch membrane reactor (CBMR) for the production of reduced-antigenicity whey protein hydrolysates with subtilisin at 60 C and pH 8.5, is presented in this paper. The operation of the CBMR comprises three steps, namely, hydrolysis, ultrafiltration and enzyme recycling, which are repeated a number of times. As a case study, a reduction of antigenicity of 1000 times was required. To this...