S)-Omeprazole is a very effective anti-ulcer medicine, and it is a significant challenge to prepare it by whole cells and to substantially increase the substrate concentration. In the chloroform-water biphasic system, resting cells of the mutant of Rhodococcus rhodochrous(R. rhodochrous)ATCC 4276 were employed to catalyze the bio-oxidation of the omeprazole sulfide for preparation of (S)-omeprazole. At a high substrate concentration(180 mM) and cell concentration(100 g/L), the bio-oxidation was optimized using response surface methodology(RSM), and the optimal yield of (S)-omeprazole obtained was 92.9% with enantiomeric excess(e.e.) (>99%), and no sulfone product was detected under the optimal conditions: the reaction temperature was 37°C, pH of phosphate buffer, 7.3 and the reaction time, 43h respectively. A quadratic polynomial model was established, which predicts the experimental data with very high accuracy according to R2 of 0.9990. The chloroform-water biphasic system may mainly contribute the significant improvement of substrate tolerance because almost all substrates may partitioned in the organic phase (water solubility of omeprazole sulfide is only about 0.5 mg/ml), resulting in little damage and inhibition to cells by substrates. The mutant of R. rhodochrous ATCC 4276 exhibited a high enantioselective, activity and substrate and product tolerance. The aerated flask provides enough oxygen for a high concentration of cells. Accordingly, the bio-oxidation is thus more promising for efficient preparation of chiral sulfoxides.

This a preprint and has not been peer reviewed. Data may be preliminary.

This paper draws on the training method of Recurrent Neural Network (RNN), By increasing the number of hidden layers of RNN and changing the layer activation function from traditional Sigmoid to Leaky ReLU on the input layer, the first group and the last set of data are zero-padded to enhance the effective utilization of data such that the improved reduction model of Denoise Recurrent Neural Network (DRNN) with high calculation speed and good convergence is constructed to solve the problem of low speaker recognition rate in noisy environment. According to this model, the random semantic speech signal with a sampling rate of 16 kHz and a duration of 5 seconds in the speech library is studied. The experimental settings of the signal-to-noise ratios are − 10dB, -5dB, 0dB, 5dB, 10dB, 15dB, 20dB, 25dB. In the noisy environment, the improved model is used to denoise the Mel Frequency Cepstral Coefficients (MFCC) and the Gammatone Frequency Cepstral Coefficents (GFCC), impact of the traditional model and the improved model on the speech recognition rate is analyzed. The research shows that the improved model can effectively eliminate the noise of the feature parameters and improve the speech recognition rate. When the signal-to-noise ratio is low, the speaker recognition rate can be more obvious. Furthermore, when the signal-to-noise ratio is 0dB, the speaker recognition rate of people is increased by 40%, which can be 85% improved compared with the traditional speech model. On the other hand, with the increase in the signal-to-noise ratio, the recognition rate is gradually increased. When the signal-to-noise ratio is 15dB, the recognition rate of speakers is 93%.

The asymmetric sulfoxidation catalyzed by soybean pod peroxidase (SPP) in water-in-oil microemulsions were carried out with the yield of 91.56% and e.e of 96.08% at the activity of SPP of 3200 U ml-1 and 50℃ for 5 h. The mechanism with a two-electron reduction of SPP-I is accompanied with a single-electron transfer to SPP-I and nonenzymatic reactions, indicating that three concomitant sub-mechanisms contribute to the asymmetric oxidation involving five enzymatic and two nonenzymatic reactions, which can represent the asymmetric sulfoxidation of organic sulfides to form enantiopure sulfoxides. With 5.44% of the average relative deviation, a kinetic model fitting experimental data very well was developed. The enzymatic reactions may follow ping-pong mechanism with substrate inhibition of H2O2 and product inhibition of esomeprazole, while nonenzymatic reactions, a power law. Those results indicate that SPP with a lower cost and higher thermal stability may be used as an effective substitute for Horseradish Peroxidase.