Abstract:
Two bacterial strains isolated from construction sites at Garima were designated as GARIMA (A) and GARIMA (B) and coded as GA (A) and GA (B) respectively. Their ability to produce carbonic anhydrase (CA) was assessed. Both GA (A) and GA (B) strains exhibited positive reactions to para-nitrophenylacetate (pNPA), leading to the formation of yellow and peach/orange colored colonies respectively. The strains were employed to generate crude CA, and the mean enzyme activities along with standard errors for CA from GA (A) and GA (B) were measured as 0.0321±0.0012 and 0.0351±0.0002 mmoles/mL-1/sec-1 respectively. Subsequently, GA (B) was selected for the large-scale production of the crude CA. Identification of GA (B) revealed it to be Alcaligenes faecalis subsp. parafaecalis strain G, through cultural, biochemical, and molecular characterizations.
The optimal substrate concentration for CA derived from GA (A) was found to be 5 mM, with an optimum temperature of 50°C and an optimal pH of 8.5. On the other hand, CA from A. faecalis subsp. parafaecalis Strain G demonstrated an optimum substrate concentration of 7 mM, an optimal temperature of 50°C, and an optimal pH of 9.5. The extracted crude CA was utilized to enhance the strength of concrete. The outcomes displayed augmented crushing strength on days 7, 14, and 28, with average values of 11.54, 15.52, and 22.28 N/mm² respectively, corresponding to a percentage strength gain of 48.29%. Scanning electron micrographs depicted visible deposits of calcium carbonate crystals on the surfaces of the concrete treated with the crude CA. These findings underscore the substantial potential of CA in bio-calcification and concrete healing applications.
ENHANCING CONCRETE BIOCALCIFICATION THROUGH INDUCTION OF CARBONIC ANHYDRASE EXPRESSION BY SOIL BACTERIAL ISOLATES, GET MORE, ACTUARIAL SCIENCE PROJECT TOPICS AND MATERIALS
