ENZYMATIC-HYDROLYSIS OF BEER BREWERS SPENT GRAIN AND THE INFLUENCE OF PRETREATMENTS

This communication describes various enzymatic treatments and chemical and physical pretreatment, using brewers' spent grain as substrate. Spent grain is the residue of malt and grain which remains in the mash-kettle after the liquefied and saccharified starch has been removed by filtration. Enzymatic hydrolysis of NaOH pretreated spent grain resulted in an amount of solubilized total sugars, which was about equal to the amount of total sugars found in the digest of the H//2SO//4 pretreated material. The amount of reducing sugars obtained from the acid-pretreated spent grain was much higher than the value found after enzymic conversion of the NaOH pretreated material, indicating that the hydrolysis products from the first treatment were almost completely in monomeric form.