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Process for co-producing lactic acid with lower polyxylose

A technology of xylooligosaccharides and lactic acid, which is applied in the field of microbial enzymatic sugar production technology and microbial fermentation, and can solve the problems of high production costs

Active Publication Date: 2013-01-16
NANJING FORESTRY UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the production cost of using glucose and starch as raw materials is still high, which limits the application of L-lactic acid, especially the application of polylactic acid as a degradable plastic in the field of environmental protection.

Method used

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  • Process for co-producing lactic acid with lower polyxylose
  • Process for co-producing lactic acid with lower polyxylose
  • Process for co-producing lactic acid with lower polyxylose

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Preparation of cellulase:

[0034] 1. Trichoderma reesei mycelium medium composition (g / L): glucose 10.0; peptone 1.0; ammonium sulfate 1.4; urea 0.3; 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; Zinc sulfate heptahydrate 0.0014; Cobalt chloride 0.002. The pH of the medium was adjusted to 4.8 with 1mol / L citrate buffer.

[0035] 2. Trichoderma reesei cellulase synthesis medium composition (g / L): glucose 1.0; pulp 10.0; peptone 1.0; ammonium sulfate 1.4; urea 0.3; potassium dihydrogen phosphate 2.0; anhydrous calcium chloride 0.3; heptahydrate Magnesium sulfate 0.3; Ferrous sulfate heptahydrate 0.005; Manganese sulfate heptahydrate 0.0016; Zinc sulfate heptahydrate 0.0014; Cobalt chloride 0.002. The pH of the medium was adjusted to 4.8 with 1mol / L citrate buffer.

[0036] 3. Cultivation of Trichoderma reesei mycelium: 50mL mycelium culture med...

Embodiment 2

[0050] Example 2: The production of xylo-oligosaccharides and the acquisition of cellulose raw materials.

[0051] The residue after extracting xylan from corncob is mainly composed of cellulose, with a content of 71.87% (dry basis) and a moisture content of 72.94%, which is a good cellulose resource. At the same time, the process of extracting xylan from corncob is actually a process of alkali pretreatment of cellulosic raw materials. Therefore, after alkali extraction, corncobs can be used as raw materials for lactic acid production without further pretreatment, and directly subjected to cellulase hydrolysis. The process of obtaining raw materials is as follows:

[0052] 1. Weigh 50g of NaOH and fully dissolve it in 702mL of distilled water, add 112g of air-dried corncob (100g absolutely dry) with a crushed particle size of 0.5-1cm, and react at 90°C for 3h.

[0053] 2. Vacuum filtration of the above reactant to remove the xylan extract, wash with 500 mL of water, and discard the...

Embodiment 3

[0056] Example 3: Preparation of lactic acid by stepwise saccharification and fermentation.

[0057] 1. Rhizopus oryzae uses the xylo-oligosaccharide production waste residue of Example 2 to produce lactic acid through stepwise saccharification and fermentation. The waste residue from the production of xylo-oligosaccharides was placed in a refrigerator at 4°C for two days to balance the moisture content, and the three elements were measured after extraction. Weigh 18.48g (absolute dry weight of 5g, of which cellulose 3.59g, moisture 13.48g) of the waste residue from the production of xylooligosaccharides in Example 2 into a 250mL Erlenmeyer flask, and add 0.45g of cellulase solution (enzyme addition 15FPIU / g cellulose), β-glucosidase 0.08g (enzyme addition 8IU / g cellulose), add buffer and distilled water, control the solid-liquid weight ratio of the system to 1:20, that is, the water volume is 100g, pH5.0± 0.5, placed in a shaker at 150r / min and enzymatically digested at 50±5℃ ...

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Abstract

The invention discloses a process for co-producing lactic acid with lower polyxylose. Solid waste residues generated in the process of preparing the lower polyxylose with corns serve as a carbon source and are fermented to prepare the lactic acid. The method includes the steps: (1) taking pretreated corncobs as raw materials and taking fungus xylanase as an initial enzyme preparation to prepare the lower polyxylose; and (2) taking the solid waste residues generated in the production process of the step (1) as raw materials and taking fungus cellulase and beta-glucosidase as enzyme preparations to prepare the lactic acid by means of rhizopus oryzae fermentation. In the method, alkali extraction is performed for hemicellulose of the corncobs by means of endo-xylanase selective enzymatic hydrolysis to prepare the lower polyxylose, the waste residues are produced by the lower polyxylose to prepare the lactic acid, and a low-cost new way is provided for the process for preparing the lower polyxylose by a microbial enzyme method and lactic acid fermentation.

Description

Technical field [0001] The invention belongs to the field of microbial enzymatic hydrolysis sugar production technology and microbial fermentation in biochemistry, and specifically relates to a process for producing xylo-oligosaccharide and co-producing lactic acid by using raw corn cob. Background technique [0002] Oligosaccharides are sugars with a low degree of polymerization formed by connecting 2 to 10 monosaccharides through glycosidic bonds. Oligosaccharides are divided into two types: ordinary oligosaccharides and functional oligosaccharides. Functional oligosaccharides refer to special biological functions, which can significantly promote the proliferation of bifidobacteria in the intestinal tract of humans or animals, and are beneficial to human or animal health. One type of oligosaccharides, the so-called bifidus factor. In addition to promoting the specific proliferation of beneficial bacteria such as bifidobacteria in the intestinal tract, another important biologi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C12P19/14C12P7/56C12R1/845
Inventor 勇强张丽李鑫李寒余世袁欧阳嘉徐勇
Owner NANJING FORESTRY UNIV