Method for preparing small-molecule galactomannan and galactomannan oligosaccharide by using corncob alkali extraction residues

[0039] Example 1

[0040] Taking corncob alkali extraction residue as carbon source to ferment and produce enzyme, the following steps are included:

[0041] (1) Pretreatment of Zeacob Extraction Residue

[0042] Take 200g of corncob extraction residue and place it in a 2L beaker, add 1L of distilled water, stir for 30 minutes, filter, transfer the filtrate to another 2L beaker, add 1L of distilled water, and stir for 30 minutes. The corncob extraction residue was dried in an oven at 40°C. The filtrate of 3 cycles is mixed, evaporated and concentrated to obtain a high-concentration sodium hydroxide solution, which is recycled for the extraction of corncob in step (1).

[0043] (2) Enzyme production medium (g / L)

[0044] Glucose 1.0, zeacob extraction residue 20.0, ammonium sulfate 4.72, urea 2.15, potassium dihydrogen phosphate 2.0, anhydrous calcium chloride 0.3, magnesium sulfate heptahydrate 0.3, ferrous sulfate heptahydrate 0.005, manganese sulfate heptahydrate 0.0016 ,

[0050] Example 2

[0051] Enzymatic hydrolysis of galactomannan to prepare small molecule galactomannan and galactomannan oligosaccharide, the steps are as follows:

[0052] (1) Directed enzymatic hydrolysis of galactomannan

[0053] The galactomannan-containing leguminous seeds (Tianjing) were mechanically pulverized to 20-100 mesh, added with distilled water according to the addition amount of 20g / L, extracted at 50°C for 24h, and centrifuged at 10,000 rpm for 10min The supernatant was obtained, and absolute ethanol was added to the supernatant, and the obtained precipitate was vacuum-dried to obtain a powdery solid of galactomannan.

[0054] Weigh above-mentioned galactomannan powdery solid 20.0g in 2L enzyme reaction tank, add distilled water, the enzyme liquid (enzyme liquid I or enzyme liquid II) obtained in Example 1, 1mol / L citric acid buffer to make the reaction The liquid volume is 1000 mL, and the mixture is fully mixed and reacted for 24 h under the conditions o