Cephalosporins are widely used antibiotics owing to their broad activity spectra and low toxicity. Many of these medically important compounds are made chemically from 7-aminodeacetoxycephalosporanic acid. At present, this intermediate is made by synthetic ring-expansion of the inexpensive penicillin G to form G-7-ADCA, followed by enzymatic removal of the side chain to obtain 7-ADCA. The chemical synthetic process is expensive, complicated and environmentally unfriendly. Environmentally compatible enzymatic process is favorable compared with chemical synthesis. In our previous research, metabolic engineered Escherichia coli strain (H7/PG15) was constructed and used as whole-cell biocatalyst for the production of G-7-ADC with penicillin G as substrate. The whole-cell biocatalysis was studied by single factor experiment, including the composition of substrates and the conversion conditions (OD600, pH, concentration of penicillin G, MOPS, glucose, time and FeSO4). After optimization, 15 mmol/L of G-7-ADCA was obtained. The process is convenient, efficient and economic. This work would facilitate the industrial manufacturing and further product research.
Anti-Bacterial Agents ; biosynthesis ; Biocatalysis ; Cephalosporins ; biosynthesis ; Escherichia coli ; metabolism ; Metabolic Engineering

The role of malate dehydrogenase 2 (MDH2) in tumors is double-sided,it has a cancerpromoting effect in some tumors and an inhibitory effect in other tumors.The function of MDH2 is related to energy metabolism,tumor resistance and its pseudo hypoxia.MDH2 plays an important role in the occurrence,development,invasion and metastasis of tumors.An in-depth understanding of the functional mechanism of MDH2 in tumors can provide new molecular targets for tumor intervention in the clinic.