Bioconversion of hydrocortisone by Absidia coerulea in wild pressure

摘要

Ceramic membranes are widely used in a large variety of industrial applications. Ceramic membranes are manufactured in flat-disc, tubular, multi-channel configurations. One of the most important characteristics of hese membrane processes is the compactness of the membrane. The exchange surface is large, which enhances filtration. There are 7, 19, 37, 61channels of ceramic membrane element applied in the industry.Hydrocortisone (HC) belongs to a class of drugs called “corticosteroids”. It is an effective anti-inflammatory drug and one of the important precursors of other steroid drugs. HC is also used to treat certain types of cancer. HC can be produced by several chemical processes and the microbial transformation. In recent years, different features of microbial transformation of HC have been investigated. The incorporation of a hydroxyl group in the 11 β -position of 17 а -hydroxypregn-4-en-3, 20-dione-21-acetate (RSA) can be performed by a great number of microorganisms in fermentation culture and /or in immobilized cells. Microbial transformation becomes one of the best methods due to low cost of RSA. However, the production of HC from RSA was of limited success, partly because of the relatively low solubility in water of RSA and O2 during the bioconversion. The pressure is one of the most important factors for the fermentation process. High pressure brings about significant changes on microorganism’s morphology, metabolic flux, gene expression, the cell membrane damage and enhancing the oxygen transfer rate. However, Very little works have been reported about the effects of mild pressure (0.1-2.5 Mpa) on viability, metabolism and catalyzing activity of microorganism cell. Especially, no literature report has been found on HC bioconversion by using the wild pressure. In order to raise the yield of hydrocortisone from RSA, the effects of mild pressure (0.1-2.5 Mpa) on viability, cell membrane permeability and catalyzing activity of Absidia coerulea (A. Coerulea) for RSA were investigated. A new method for improving the production of hydrocortisone from RSA by A. Coerulea in wild pressure was developed. The results showed that morphology of A. Coerulea mycelium pellet was changed in wild pressure. A. Coerulea mycelium pellet seemed to be loosed. The viability of A. Coerulea mycelium in wild pressure could keep high level. Cell membrane permeability of A. Coerulea mycelium in wild pressure was improved. The production of hydrocortisone with atmosphere as the pressure media (0.5 Mpa) was higher significantly than that with N2 as the pressure media, the production of hydrocortisone was enhanced over 1.12-folds. Moreover, the production of hydrocortisone with atmosphere as the pressure media (0.5 Mpa) could be increased by the addition of H2O2 (60 Mm), the production of hydrocortisone in wild pressure was enriched by over 5 % in comparison to control (0.1 Mpa).The major composition of bioconverted mixture was reduced from 9 to 6. It was indicated that the new approach (wild pressure) obtained in this work possessed a high potential for the industrial production of HC.