Horizontal Fiber Fermenter
It has been found that attaching yeast to a support results in a reaction converting sugar to alcohol that is up to nine times that when yeast is put in solution. Also investigators have found that Zymomonas reacts two to three times faster than yeast. We have found that Z. mobilis attaches quite readily to fibers. The advantage of flexible fibers is that biomass can be dislodged. Clogging is the main problem with ceramic support columns. In vertical columns, CO2 generated at the bottom, travels all the way up the column, dislodging bacteria, and biomass generated at the top of the column, travels down, coating live cells. In a horizontal fermenter, CO2 and biomass exit easier, and a way has been found to dislodge dead cells, either with striker bars or ultrasonics. The striker bars move back and forth and have internal heaters, so biomass is removed from the, too, resulting in better heat transfer. The fibers can be cotton, or, in the case where other bacteria convert cellulose to sugar and sugar to alcohol in one step, a ceramic fiber is being developed.