A kind of method of degrading corn stover

Abstract

A method for degrading corn stalks, characterized in that: after the corn stalks are mechanically crushed, sieved, and dried, they are used for Cu 2+ Modified Fe 3 O4‑NH 2 ‑PEI magnetic nanoparticles as a carrier of immobilized laccase to degrade lignin in corn stalks, then recover the immobilized laccase, boil the degraded corn stalks and add NaOH for washing, then add cellulase to further degrade fibers white. The method of the invention enhances the affinity between the immobilized laccase and the substrate, improves the stability and activity of the laccase in the application process, thereby improving the degradation efficiency, and the degradation rate of the lignin reaches more than 40.76%. The inhibition of cellulase activity by degradation products such as immobilized laccase and phenolic substances produced by degradation is eliminated, thereby ensuring cellulase activity and improving the conversion rate of cellulose, and the conversion rate reaches 46.85%.

Description

technical field

[0001] The invention belongs to the field of straw degradation, and in particular relates to a method for degrading corn straw with immobilized laccase. Background technique

[0002] Corn stover is a very abundant renewable resource, and the lignocellulose contained in it is the most valuable bioenergy. The lignocellulose composition and structure of different plants are different, and the lignocellulose of corn stover is mainly composed of cellulose, hemicellulose and lignin. However, cellulose, hemicellulose, and lignin in corn stover are intertwined to form a cell wall structure. This intertwined structure determines that the degradation of any type of component must be restricted by other components, especially lignin and hemicellulose. The cellulose is bound in the form of covalent bonds to wrap the cellulose, forming a natural barrier that hinders the contact between cellulase and cellulose molecules, thus limiting the decomposition of cellulose and ma...

Examples

Embodiment 1

[0045] A method for degrading corn stalks, comprising the following steps:

[0046] (1) After the corn stalks are mechanically crushed, pass through a 40-mesh sieve, and then dry at 105° C. for later use;

[0047] (2) Cu 2+ Modified Fe 3 O4-NH 2 -PEI magnetic nanoparticles were dissolved in NaAC-HAC buffer solution containing laccase, and treated with shaking at 150 rpm for 40min at 25°C; after the reaction, the prepared Cu 2+ Modified Fe 3 O4-NH 2 - PEI laccase magnetic nanoparticles and supernatant separation; ultrapure water for Cu 2+ Modified Fe 3 O4-NH 2 -PEI laccase magnetic nanoparticles were washed continuously until no laccase activity was detected in the detergent; the pH of NaAC-HAC buffer was 4.6, the concentration of laccase was 0.5mg / mL, Cu 2+ Modified Fe 3 O4-NH 2 -The mass volume ratio of PEI magnetic nanoparticles to NaAC-HAC buffer solution is 1mg: 10mL;

[0048] (3) Shake the immobilized laccase prepared in step (2), the corn stalks treated in ste...

Embodiment 2

[0052] A method for degrading corn stalks, comprising the following steps:

[0053] (1) After the corn stalks are mechanically crushed, pass through a 40-mesh sieve, and then dry at 105° C. for later use;

[0054] (2) Immobilize laccase on Cu 2+ Modified Fe 3 O4-NH 2 -On PEI magnetic nanoparticles, immobilized laccase was formed, specifically Cu 2+ Modified Fe 3 O4-NH 2 -PEI magnetic nanoparticles were dissolved in NaAC-HAC buffer solution containing laccase, and shaken at a rate of 150 rpm for 70 min at 25°C; after the reaction, the prepared Cu 2+ Modified Fe 3 O4-NH 2 - PEI laccase magnetic nanoparticles and supernatant separation; ultrapure water for Cu 2+ Modified Fe 3 O4-NH 2 -PEI laccase magnetic nanoparticles were washed continuously until no laccase activity was detected in the detergent; the pH of NaAC-HAC buffer was 4.6, the concentration of laccase was 4mg / mL, Cu 2+ Modified Fe 3 O4-NH 2 -The mass volume ratio of PEI magnetic nanoparticles to NaAC-HAC b...

Embodiment 3

[0059] A method for degrading corn stalks, comprising the following steps:

[0060] (1) After the corn stalks are mechanically crushed, pass through a 40-mesh sieve, and then dry at 105° C. for later use;

[0061] (2) Immobilize laccase on Cu 2+ Modified Fe 3 O4-NH 2 -On PEI magnetic nanoparticles, immobilized laccase was formed, specifically Cu 2+ Modified Fe 3 O4-NH 2 -PEI magnetic nanoparticles were dissolved in NaAC-HAC buffer solution containing laccase, and shaken at a rate of 150 rpm for 50 min at 25°C; after the reaction, the prepared Cu 2+ Modified Fe 3 O4-NH 2 - PEI laccase magnetic nanoparticles and supernatant separation; ultrapure water for Cu 2+ Modified Fe 3 O4-NH 2 - PEI laccase magnetic nanoparticles were washed continuously until no laccase activity was detected in the detergent; the pH of NaAC-HAC buffer was 4.6, the concentration of laccase was 20.5 mg / mL, Cu 2+ Modified Fe 3 O4-NH 2 -The mass volume ratio of PEI magnetic nanoparticles to NaAC-...

technical field

[0001] The invention belongs to the field of straw degradation, and in particular relates to a method for degrading corn straw with immobilized laccase. Background technique

[0002] Corn stover is a very abundant renewable resource, and the lignocellulose contained in it is the most valuable bioenergy. The lignocellulose composition and structure of different plants are different, and the lignocellulose of corn stover is mainly composed of cellulose, hemicellulose and lignin. However, cellulose, hemicellulose, and lignin in corn stover are intertwined to form a cell wall structure. This intertwined structure determines that the degradation of any type of component must be restricted by other components, especially lignin and hemicellulose. The cellulose is bound in the form of covalent bonds to wrap the cellulose, forming a natural barrier that hinders the contact between cellulase and cellulose molecules, thus limiting the decomposition of cellulose and ma...

Examples

Embodiment 1

[0045] A method for degrading corn stalks, comprising the following steps:

[0046] (1) After the corn stalks are mechanically crushed, pass through a 40-mesh sieve, and then dry at 105° C. for later use;

[0047] (2) Cu 2+ Modified Fe 3 O4-NH 2 -PEI magnetic nanoparticles were dissolved in NaAC-HAC buffer solution containing laccase, and treated with shaking at 150 rpm for 40min at 25°C; after the reaction, the prepared Cu 2+ Modified Fe 3 O4-NH 2 - PEI laccase magnetic nanoparticles and supernatant separation; ultrapure water for Cu 2+ Modified Fe 3 O4-NH 2 -PEI laccase magnetic nanoparticles were washed continuously until no laccase activity was detected in the detergent; the pH of NaAC-HAC buffer was 4.6, the concentration of laccase was 0.5mg / mL, Cu 2+ Modified Fe 3 O4-NH 2 -The mass volume ratio of PEI magnetic nanoparticles to NaAC-HAC buffer solution is 1mg: 10mL;

[0048] (3) Shake the immobilized laccase prepared in step (2), the corn stalks treated in ste...

Embodiment 2

[0052] A method for degrading corn stalks, comprising the following steps:

[0053] (1) After the corn stalks are mechanically crushed, pass through a 40-mesh sieve, and then dry at 105° C. for later use;

[0054] (2) Immobilize laccase on Cu 2+ Modified Fe 3 O4-NH 2 -On PEI magnetic nanoparticles, immobilized laccase was formed, specifically Cu 2+ Modified Fe 3 O4-NH 2 -PEI magnetic nanoparticles were dissolved in NaAC-HAC buffer solution containing laccase, and shaken at a rate of 150 rpm for 70 min at 25°C; after the reaction, the prepared Cu 2+ Modified Fe 3 O4-NH 2 - PEI laccase magnetic nanoparticles and supernatant separation; ultrapure water for Cu 2+ Modified Fe 3 O4-NH 2 -PEI laccase magnetic nanoparticles were washed continuously until no laccase activity was detected in the detergent; the pH of NaAC-HAC buffer was 4.6, the concentration of laccase was 4mg / mL, Cu 2+ Modified Fe 3 O4-NH 2 -The mass volume ratio of PEI magnetic nanoparticles to NaAC-HAC b...

Embodiment 3

[0059] A method for degrading corn stalks, comprising the following steps:

[0060] (1) After the corn stalks are mechanically crushed, pass through a 40-mesh sieve, and then dry at 105° C. for later use;

[0061] (2) Immobilize laccase on Cu 2+ Modified Fe 3 O4-NH 2 -On PEI magnetic nanoparticles, immobilized laccase was formed, specifically Cu 2+ Modified Fe 3 O4-NH 2 -PEI magnetic nanoparticles were dissolved in NaAC-HAC buffer solution containing laccase, and shaken at a rate of 150 rpm for 50 min at 25°C; after the reaction, the prepared Cu 2+ Modified Fe 3 O4-NH 2 - PEI laccase magnetic nanoparticles and supernatant separation; ultrapure water for Cu 2+ Modified Fe 3 O4-NH 2 - PEI laccase magnetic nanoparticles were washed continuously until no laccase activity was detected in the detergent; the pH of NaAC-HAC buffer was 4.6, the concentration of laccase was 20.5 mg / mL, Cu 2+ Modified Fe 3 O4-NH 2 -The mass volume ratio of PEI magnetic nanoparticles to NaAC-...

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