In PHF trials, where solid-free preparations were required, residual hull solids were removed following hydrolysis by centrifugation for 10 min at 25,000 x g at 4 oC. The clear supernatants were recovered, adjusted to pH 7.5 with 1 M KOH, analyzed for soluble CHO and then used for fermentation trials. S-7 medium served as the primary control. The hydrolysates, which supplied soluble CHO, were supplemented with all the S-7 medium ingredients except glucose. Based on their soluble CHO concentrations, hydrolysate volumes used in media preparation were calculated so as to reach a final soluble CHO concentration of 20 g/L to match the glucose concentration of the control. Greater or lesser vol- umes of make-up water were included in the medium, so all flasks had the same volumes. Media containing hull preparations that were identically processed, but without enzyme treatment (referred to as "SBH extracts") served as secondary controls. The media were filter sterilized, and then inoculated with B. subtilis 40688-E4. Fermentations were carried out as described above.