Patent ID: 6294351
Filing Date: 2001-09-25
Classification: C09K,C12N,C12R

Abstract:
A method of preparing a mixture of modified bacterial strains selected through nutritional stress to upgrade a coal slurry which comprises:(i) providing at least a thermophilic bacterial strain which grows on oil;(ii) nutritionally stressing said thermophilic bacterial strain through sequential conditions comprising decreasing crude oil concentration and increasing coal concentration until coal is essentially the sole carbon source and increasing salinity and trace metal concentration stepwise until said thermophilic bacterial strain is capable of growing on coal as essentially the sole carbon source at a salinity level between 1.5 weight % to 35 weight %, a trace metal concentration from about 0.01 weight % to about 10 weight %, and pressure from about atmospheric to about 2500 psi;(iii) recovering said nutritionally stressed bacterial strain; and(iv) forming a mixture of said nutritionally stressed thermophilic bacterial strain with other thermophilic bacterial strains which have been nutritionally stressed according to steps (ii) and (iii);(v) recovering said mixture of nutritionally stressed thermophilic bacterial strains.