Assessment of the efficiency of synergistic photocatalysis on penicillin G biodegradation by whole cell Paracoccus sp.

BACKGROUND: The Paracoccus sp. strain isolated from sludge was identified and evaluated for catalytic activity in the degradation of penicillin G. RESULTS: High degradation efficiency and synergistic catalytic effects of the whole cell and visible light without additional catalysts were observed. The key factors influencing the degradation and kinetics of penicillin G were investigated. The results showed the phenylacetic acid, which was produced during penicillin G biodegradation, exhibited stronger inhibiting effects on KDSPL-02. However, this effect was reduced by visible light irradiation without any additional photocatalyst; furthermore, the rate of penicillin G biodegradation was accelerated, reaching a 100% rate in 12 h at a penicillin G concentration of 1.2 g/L. Four key intermediates produced during penicillin G degradation were isolated and identified by LC-MS, 1H NMR, and 13C NMR. Enzymes involved in the PAA pathway were proposed from a genomic analysis of KDSPL-02. CONCLUSIONS: These results provide a new method for bio-degrading of penicillin or other antibiotic pollutants using photoaccelerating biocatalysts with greater efficiency and more environmentally friendly conditions.

Enzyme-catalyzed biodegradation of penicillin fermentation residues by ß-lactamase OtLac from Ochrobactrum tritici.

BACKGROUND: Biodegradation of antibiotics is a promising method for the large-scale removal of antibiotic residues in the environment. However, the enzyme that is involved in the biodegradation process is the key information to be revealed. RESULTS: In this study, the beta-lactamase from Ochrobactrum tritici that mediates the biodegradation of penicillin V was identified and characterized. When searching the proteins of Ochrobactrum tritici, the ß-lactamase (OtLac) was identified. OtLac consists of 347 amino acids, and predicted isoelectric point is 7.0. It is a class C ß-lactamase according to BLAST analysis. The coding gene of OtLac was amplified from the genomic DNA of Ochrobactrum tritici. The OtLac was overexpressed in E. coli BL21 (DE3) and purified with Ni2+ column affinity chromatography. The biodegradation ability of penicillin V by OtLac was identified in an in vitro study and analyzed by HPLC. The optimal temperature for OtLac is 32 â„ƒ and the optimal pH is 7.0. Steady-state kinetics showed that OtLac was highly active against penicillin V with a Km value of 17.86 µM and a kcat value of 25.28 s-1 respectively. CONCLUSIONS: OtLac demonstrated biodegradation activity towards penicillin V potassium, indicating that OtLac is expected to degrade penicillin V in the future.

Isolation and Characterization of Ochrobactrum tritici for Penicillin V Potassium Degradation.

Substantial concentrations of penicillin V potassium (PVK) have been found in livestock manure, soil, and wastewater effluents, which may pose potential threats to human health and contribute to the emergence of penicillin-resistant bacterial strains. In this study, bacterial strains capable of degrading PVK were isolated from sludge and characterized. Strain X-2 was selected for biodegradation of PVK. Based on morphological observations and 16S rRNA gene sequencing, strain X-2 was identified as an Ochrobactrum tritici strain. To enhance the PVK degradation ability of PVK, a whole-cell biodegradation process of Ochrobactrum tritici X-2 was established and optimized. In the whole-cell biodegradation process, the optimal temperature and pH were 30°C and 7.0, respectively. Under the optimized conditions, the degradation rate using 0.5 mg/ml PVK reached 100% within 3 h. During biodegradation, two major metabolites were detected: penicilloic acid and phenolic acid. The present study provides a novel method for the biodegradation of PVK using Ochrobactrum tritici strains, which represent promising candidates for the industrial biodegradation of PVK.IMPORTANCE Substantial concentrations of penicillin V potassium (PVK) have been found in the environment, which may pose potential threats to human health and contribute to the emergence of penicillin-resistant bacterial strains. In this study, antibiotic-degrading bacterial strains for PVK were isolated from sludge and characterized. Ochrobactrum tritici was selected for the biodegradation of PVK with high efficiency. To enhance its PVK degradation ability, a whole-cell biodegradation process was established and optimized using Ochrobactrum tritici The degradation rate with 0.5 mg/ml PVK reached 100% within 3 h. The potential biodegradation pathway was also investigated. To the best of our knowledge, the present study provides new insights into the biodegradation of PVK using an Ochrobactrum tritici strain, a promising candidate strain for the industrial biodegradation of ß-lactam antibiotics.

Simultaneous production of propionic acid and vitamin B12 from corn stalk hydrolysates by Propionibacterium freudenreichii in an expanded bed adsorption bioreactor.

Vitamin B12 and propionic acid that were simultaneous produced by Propionibacterium freudenreichii are both favorable chemicals widely used in food preservatives, medicine, and nutrition. While the carbon source and propionic acid accumulation reflected fermentation efficiency. In this study, using corn stalk as a carbon source and fed-batch fermentation process in an expanded bed adsorption bioreactor was studied for efficient and economic biosynthesis of acid vitamin B12 and propionic. With liquid hot water pretreated corn stalk hydrolysates as carbon source, 28.65 mg L-1 of vitamin B12 and 17.05 g L-1 of propionic acid were attained at 168 h in batch fermentation. In order to optimize the fermentation outcomes, fed-batch fermentation was performed with hydrolyzed corn stalk in expanded bed adsorption bioreactor (EBAB), giving 47.6 mg L-1 vitamin B12 and 91.4 g L-1 of propionic acid at 258 h, which correspond to product yields of 0.37 mg g-1 and 0.75 g g-1, respectively. The present study provided a promising strategy for economically sustainable production of vitamin B12 and propionic acid by P. freudenreichii fermentation using biomass cornstalk as carbon source and expanded bed adsorption bioreactor.