COMPARISON OF CALCIUM CARBONATE PRECIPITATION (CCP) AND YEAST UREA (YU) CULTURE MEDIA ON HYDROCARBONOCLASTIC BACTERIA ENDOSPORES FORMATIONCarlanetta Kusuma Duhita and Enny Zulaika
Some of hydrocarbonoclastic bacteria species are able to form endospores and potentially to be applied as additional ingredients to strengthen concrete structures. Bacteria endospores are highly resistant in extreme environment such as inner part of concrete which has pH of 13. The aim of this study was to compare the formation of hydrocarbonoclastic bacterial endospores on CCP and YU media. Bacteria isolates were Bacillus JA1, JB2, AK4, SU1, Lysinibacillus JB2 and Sporosarcina JA4. Isolates were cultured in CCP and YU media for 24 hours. Generated endospores from these media were stained using malachite green and observed under microscope. Bacteria vegetative cells were removed from culture media through cell lysis using a shock treatment at 70 Â°C utilize thermostat waterbath. Viable endospores were observed after incubation for 7 days. Our study showed all isolates are able to form endospores. Bacteria isolates produced more endospore in YU media than CCP media. Lysinibacillus JB2 produced highest amount of endospores (4.9Ã106 in CCP media and 5.4Ã106 in YU media) and its endospores also showed the best viability after heat shock treatment for 20 minutes.