Stenotrophomonas strain DP30; a marine bacteria capable of precipitating calcium carbonate

Abstract

This study aimed to evaluate the calcium carbonate precipitation potential of culturable bacteria found in sea surface water. Ureolytic strains were selected using Stuart’s broth. In the preliminary screening, strain DP30 was selected and used in further experiments. Based on the morphological, physiological, and biochemical characteristics with phylogenetic analysis of the 16S rRNA sequencing, the selected strain was identified as Stenotrophomonas maltophilia. DP30 showed the highest urease activity on the 7th day at 28 °C. In addition, it was found that the isolate can show urease activity in low pH environmental conditions such as pH 5. The strain DP30 precipitated CaCO3 on solid Urea-CaCl2 and B4 media but exhibited different crystal morphologies. Plate-like crystals appeared on solid Urea-CaCl2 media, while the strain produced dihydrate calcium oxalate and rhombohedral crystals on solid B4 media. EDS analysis confirmed that the precipitated minerals were composed solely of calcium, carbon, and oxygen. Furthermore, the study showed that S. maltophilia strain DP30 was able to precipitate calcium carbonate under aerobic conditions without urea hydrolysis. These findings suggest that the DP30 strain may have the potential for use in self-healing concrete applications. Moreover, calcium carbonate precipitation without urea hydrolysis where ammonia is produced will provide an environmentally friendly application.