[Specific gravity of the dried biomass of pure bacterial cultures]

The weight of wet and dry biomass taken from colonies after growth on MPA was determined in pure bacterial cultures of Pseudomonas denitrificans and Brevibacterium imperiale, and the number and dimensions of bacterial cells in dry preparations of the same colonies were measured by means of membrane filters. The average specific weight of dry biomass was found to be 1.68 and 1.62. In calculating the weight of bacterial biomass in pure cultures and natural cenoses, its volume should be assayed taking into account the number and dimensions of the cells in dry preparations on membrane filters and multiplying by a coefficient 1.6.