Abstract: In China, about 130, 000 tons of different kinds of extract residues are obtained per annum in the tannin extract industrial production. To find an effective pathway for utilization of this resource has a very important significance.This work is concerned in the production of fodder yeast from tannin extract residues using acid hydrolysis method.Its main purpose is to clarify whether the tannin extract residues as raw material are suitable to the percolation hydrolysis technology at high temperature using dilute sulfuric acid, and meanwhile to investigate the conformability of the hydrolyzate neutralized as substrate for the fodder yeast fermentation.The chemical analytical data of five kinds of tannin extract residues from four manufactories showed that the sugar content of two valonea extract residues is the highest, up to 56.78% and 59.70%, respectively.Therefore these residues were chosen as raw materials in this experiment.When these residues were subjected to hydrolysis for 60 minutes with dilute sulfuric acid from 0.5% to 0.8%, at temperatures from 180 to 190℃, its sugar yields averaged about 40%, corresponding to 67% of the theoretical sugar yields, approximating to the general level of hydrolysis industrial production.When the substrate was fermented with Candida tropicalis, the yeast yields range from 36.71% to 39.80% of the reducing sugar content, and the protein content of yeast amounts from 43.64% to 48.68%, approximating to the general level of hydrolysis industrial production.Research results revealed that utilization of valonea extract residues for production of fodder yeast is basically feasible by means of acid hydrolysis in respect of technique.The production cost is economically near to that from other kinds of raw material used in hydrolysis industry.

Key words: acid hydrolysis, tannin extract residues, yeast