Bioremediation of historic architectural heritages by Sporosarcina pasteurii

Laboratory experiments were conducted to protect and consolidate historic architectural heritages by bacterially induced carbonate mineralization forming a deposition layer on the surface of marble samples. Then, the effects of crystal phase and growth of the mineralized layer as well as the deposited crystal on the porosity of samples and on the efficiency of bonding and protection were analyzed by means of XRD, SEM, mercury intrusion porosimeter (MIP) and ultrasonic test. Results show that the mineral crystal is composed of calcite and vaterite phases, that bacteria act as nucleation sites in the precipitation of the mineral crystal uniformly depositing on the sample surface, that the precipitation has no significant effect on the pore size distribution of samples rather than results in a porosity decrease by 22.2%, and that the mineral crystal strongly attaches the substratum. It is thus concluded that the bacterially-induced biomineralization is effective in remediating historic stone architectural heritages and can be an ecological and novel alternative to traditional techniques.