Production of clinically efficient uricase enzyme induced from different strains of Pseudomonas aeruginosa under submerged fermentations and their kinetic properties

Maximization of uricase production in a column bioreactor through response surface methodology-based optimization

Uricase (EC 1.7.3.3) is an oxidoreductase enzyme that is widely exploited for diagnostic and treatment purposes in medicine. This study focuses on producing recombinant uricase fromE. coliBL21 in a bubble column bioreactor (BCB) and finding the optimal conditions for maximum uricase activity. The three most effective variables on uricase activity were selected through the Plackett-Burman design from eight different variables and were further optimized by the central composite design of the response surface methodology (RSM). The selected variables included the inoculum size (%v/v), isopropylβ-d-1-thiogalactopyranoside (IPTG) concentration (mM) and the initial pH of the culture medium. The activity of uricase, the final optical density at 600 nm wavelength (OD600) and the final pH were considered as the responses of this optimization and were modeled. As a result, activity of 5.84 U·ml-1and a final OD600of 3.42 were obtained at optimum conditions of 3% v/v inoculum size, an IPTG concentration of 0.54 mM and a pH of 6.0. By purifying the obtained enzyme using a Ni-NTA agarose affinity chromatography column, 165 ± 1.5 mg uricase was obtained from a 600 ml cell culture. The results of this study show that BCBs can be a highly effective option for large-scale uricase production.

Combinatorial approach for screening and assessment of multiple therapeutic enzymes from marine isolate Pseudomonas aeruginosa AR01

Industrialization and modernization have led to humans being more susceptible to diseases. Therapeutic enzymes from traditional earthbound bacterial origin result have less therapeutic value. Hence, the hunt for a novel source of enzymes is indispensable. Twenty different marine bacterial strains were isolated from mangrove soil around S. P. Pattinum, Tamilnadu, India. From repeated qualitative and quantitative experiments, the study results were that, out of twenty bacterial isolates, only one Gram-negative bacterium was positive for multiple therapeutic enzymes such as asparaginase, glutaminase, uricase and collagenase. Based on its 99% 16S rRNA sequence similarity with Pseudomonas aeruginosa, the isolate was designated as Pseudomonas aeruginosa AR01. Modified minimal medium amended with asparagine results in a simple and cost-effective, one-pot production medium for enhanced production and easy purification of all therapeutic enzymes. The biochemical studies imply that the therapeutic enzymes from P. aeruginosa AR01 may find a significant role in medical applications. The in vitro cytotoxic study reveals that the anticancer enzyme from P. aeruginosa is considerably effective with an IC50 value of 12 μg mL-1 against K-562 cell line. Colony PCR was performed for the detection of specific therapeutic enzyme-coding genes in the genome of P. aeruginosa AR01. PCR results confirm that P. aeruginosa AR01 possesses nucleotide regions for corresponding therapeutic enzymes in its gene cluster. BLASTN and BLASTX analyses of the partial nucleotide sequences of therapeutic enzymes were deposited in GenBank. The results appear so promising that Pseudomonas aeruginosa AR01 may be a potent candidate for medical biotechnology.