ACIDOGENIC FERMENTATION OF CORN STOVER

Corn stover was fermented by anaerobic acidogenic bacteria to produce volatile (C2-C6) organic acids. Mild pretreatment with dilute alkali solutions produced a two-fold increase in fermentability. A mixture of lime and sodium carbonate was found to be a better pretreatment agent than sodium hydroxide. Methane generation was inhibited by low temperature (≤ 25°C) and high solids [≥ 2.5% (w/v)] fermentation. Volatile acid yields of 0.5-0.55 g acetic acid equiv/g dry ash-free (DAF) stover could be obtained in batch fermentations. Several extractants and extraction solvents for organic acids were found to be nontoxic to acidogenic fermentation. The data show that acidogenic fermentation can produce useful volatile fatty acids in high yields from a complex lignocellulosic feedstock. These fermentations are nonsterile, need no stirring, and are easy to run. Moreover, cellulose, pentosans, and other carbohydrates are directly utilized by acidogenic bacteria. Hence, acidogenic fermentation could be useful in converting biomass to chemical feedstocks and fuel. © 1981 John Wiley & Sons, Inc.