Removal of Organic Acid from Hemicellulose Hydrolysate by Bio-oxidation to Produce Alkali

Abstract:

Pichia galeiforms B-10 has a good ability to degrade organic acid in hemicellulose hydrolysate, and this depickling activity of the strain is mainly affected by the initial pH value of hydrolysate. If the initial pH value of hemicellulose hydrolysate was adjusted above 5.0, Pichia galeiforms B-10 would exhibit an excellent capability of depickling fermentation without any other treatment. During the metabolism of organic acid salt by Pichia galeiforms B-10, alkali products were generated and this caused the raising of pH value. Therefore, under the condition of pH > 5.0, if only the acid supplying speed (by adding hydrolysate with low pH value) was adjusted to be in balance with the acid metabolizing speed, the fermentation system would always be kept in a high pH circumstance which was advantageous to the metabolism of organic acid by yeast. This mode, by using bio?oxidation to produce alkali for the continuous depickling fermentation, effectively reduced the addition of alkali during the neutralization of hemicellulose hydrolysate, and finally lowered the processing cost and generated less pollutant.

Key words:Hemicellulose hydrolysate, Bio-oxidation to produce alkali, Organic acid