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Hai-Qing Wang

Publications and source records attributed to Hai-Qing Wang.

2 recordsLinked to original sources

[Modelling a penicillin fed-batch fermentation using least squares support vector machines].

The biochemical processes are usually characterized as seriously time varying and nonlinear dynamic systems. Building their first-principle models are very costly and difficult due to the absence of inherent mechanism and efficient on-line sensors. Furthermore, these detailed and complicated models do not necessary guarantee a good performance in practice. An approach via least squares support vector machines (LS-SVM) based on Pensim simulator is proposed for modelling the penicillin fed-batch fermentation process, and the adjustment strategy for parameters of LS-SVM is presented. Based on the proposed modelling method, the predictive models of penicillin concentration, biomass concentration and substrate concentration are obtained by using very limited on-line measurements. The results show that the models established are more accurate and efficient, and suffice for the requirements of control and optimization for biochemical processes.

Biomass↗

[Hydroxylation of 16alpha, 17alpha-epoxy-4-pregenene-3, 20-dione by Absidia coerulea with pseudo-crystallo feed].

The 11-hydroxylation of 16alpha,17alpha-epoxy-4-pregenene-3,20-dione as a useful intermediate for the preparation of hormones can be achieved by the mycelium of Absidia coerulea at higher conversion rate than using other strains. In this paper 16alpha,17alpha-epoxy-4-pregenene-3,20-dione mixed with a little water, beta-cyclodextrin, Tween-80 was introduced into the fermentation broth after ultrasonication to increase pseudo-water-solubility of the hydrophobic substrate. This pseudo-crystallo feed could avoid the toxicity of organic solvents and was more available for the microbial transformation. The multi layer feed-forward neural network was used to setup a model which indicated the relationship between medium and feed components and the conversion rate. Particle swarm optimization (PSO), which was a stochastic global optimization algorithm and of which the convergence speed was high, was applied to obtain the optimal concentration of the medium and feed components. At optimum conditions with the pseudo-crystallo feed, the conversion rate of 16alpha,17alpha-epoxy-4-pregenene-3,20-dione at an initial concentration of 10 g/L was 87.5% in shaking flasks. The conversion rate of the substrate was up to 86.6% at higher concentration of 20 g/L feed in a 3.7 L fermentor.

Absidia↗