Figure 3: Scanning electron microscopic (SEM) images of P. valderianum BDU20041 and O. willei BDU130791. The filaments of P. valderianum BDU20041 (a) and O. willei BDU130791 (b) grown in ASN III medium. (c and d) reveal the calcium carbonate deposits as the calcite crystals over the filaments of P. valderianum BDU20041 and O. willei BDU130791. The precipitates formed during growth of P. valderianum (e) and O. willei (f) showed presence of rhambohedral structures typical of calcite.