Scanning electron micrograph of adsorbed cells of C. acetobutylicum P262 onto bonechar. a) bonechar (magnification 5500); b) adsorbed cells onto bonechar (magnification 2200); c) transmission electron micrograph of adsorbed cells (magnification 2300). Similar figures (3b, c) with different magnification were published previously in the following article: Qureshi N, Paterson AHJ, Maddox IS: Model for continuous production of solvents from whey permeate in a packed bed reactor using cells of Clostridium acetobutylicum immobilized by adsorption onto bonechar. Appl Microbiol Biotechnol 1988, 29: 323–328. Figure 3 is reprinted with permission from Springer, Germany (see above article).