FRESENIUS ENVIRONMENTAL BULLETIN, vol.31, no.5, pp.5185-5191, 2022 (SCI-Expanded)
In this study, Streptococcus bovis lichenase gene was cloned into recombinant vector pBR325SE2 (pBR325 plus Spirulina platensis serine esterase gene) and thus the integrative vector pBR325SLic was constructed. The pBR325SLic vector was transferred into the competent E. coli XL1 Blue MRF' cells. Transformed bacteria E.co/i/pBR325SLic grew in the selective medium containing chloramphenicol (Cm) while there were no non-transformant in the same medium. 1800 bp gene product using recombinant vector as template in PCR experiment was showed on the agarose gel. Lichenase production by recombinant E. coli cells cultivated in liquid media reached a maximum at 36 h, with levels of 192.8 mu mol mg(-1) protein/min. Optimum pH and temperature values for recombinant enzyme activity were 7.0 and 40 degrees C respectively. The recombinant enzyme lost most of its activity after pre-incubation at 50 degrees C for 15 min. However, the enzyme maintained its stability significantly in the pH range 4.0-10.0. The molecular weight of the enzyme was estimated to be 95.6 kDa by sodium dodecyl sulphate-polyacrylamide gel electrophoresis.