阅读说明：本技术 一种秸秆好氧固态发酵高产腐殖酸的工艺 (Process for high yield of humic acid by straw aerobic solid state fermentation ) 是由 王永忠 刘帅 王楠 丁柯 羊羊尤佳 吉婕莉 刘乙 于 2020-05-22 设计创作，主要内容包括：本发明公开了一种秸秆好氧固态发酵高产腐殖酸的工艺,通过单因素实验,研究了基质颗粒大小为0.2-12mm,通风量为0.1-1.2L/min和纤维素酶添加量为5-20FPU/g基质条件下发酵基质温度、pH、TOC、TN、C/N、木质纤维素含量及腐殖酸产量的变化,获得了最优的发酵高产腐殖酸的工艺。在最优发酵条件下,腐殖酸产量为352.5g kg<Sup>-1</Sup>；C/N降至10.53；木质素、纤维素和半纤维素的降解率分别为69.83％、45.58％和78.3％。将发酵所产腐殖酸用于青菜种子发芽率试验,相比对照组不同浓度的腐殖酸溶液(10％、20％、30％和40％)种子发芽率分别提高了6.55％、6.95％、6.95％和12.2％。通过分析不同发酵时间基质细菌群落结构变化,结果表明,Pseudoxanthomonas、Lactobacillus、Phenylobacterium、Pseudomonas、Brevundimonas、Rhizobium和Chryseobacterium为秸秆好氧发酵生物转化腐殖酸过程中的优势菌属。(The invention discloses a process for producing humic acid with high yield by aerobic solid-state fermentation of straws, which researches the changes of the temperature, pH, TOC, TN, C/N, lignocellulose content and humic acid yield of a fermentation substrate under the conditions that the substrate particle size is 0.2-12mm, the ventilation volume is 0.1-1.2L/min and the cellulase addition amount is 5-20FPU/g substrate through a single-factor experiment, and obtains the optimal process for fermenting high-yield humic acid. Under the optimal fermentation condition, the yield of humic acid is 352.5g kg ‑1 (ii) a C/N is reduced to 10.53; the degradation rates of lignin, cellulose and hemicellulose were 69.83%, 45.58% and 78.3%, respectively. Will be provided withWhen the humic acid produced by fermentation is used for the germination rate test of the green vegetable seeds, compared with humic acid solutions (10%, 20%, 30% and 40%) with different concentrations in a control group, the germination rates of the seeds are respectively improved by 6.55%, 6.95% and 12.2%. By analyzing the structural change of the substrate bacterial community at different fermentation times, the result shows that pseudomonad, Lactobacillus, Phenylobacterium, Pseudomonas, Brevundimonas, Rhizobium and Chryseobacterium are the dominant genera in the process of biologically converting humic acid by the aerobic fermentation of straws.)

1. A process for producing humic acid with high yield by straw aerobic solid state fermentation is characterized by comprising the following steps:

1) crushing dried straw stalks, and screening a substrate with the substrate particle size of 0.2-12mm by using sieves with different meshes for later use; weighing 200-400g of sludge and materials with different substrate particle sizes, mixing and adding into a reactor; setting ventilation quantity at 0.1-0.9L/min and cellulase addition quantity at 5-20FPU/g substrate, respectively, and fermenting to obtain the optimal fermentation substrate with particle size of 0.5-1.0 mm;

2) respectively setting the ventilation quantity to be 0.1-0.9L/min and the cellulase addition quantity to be 5-20FPU/g substrate under the condition of the optimal fermentation substrate particle size, and fermenting under the condition to obtain the optimal ventilation quantity to be 0.5-0.8L/min;

3) under the conditions of the optimal fermentation substrate particle size and the optimal ventilation quantity, the addition amount of the cellulase is set to be 5-20FPU/g substrate, and the optimal cellulase addition amount is 10-15FPU/g substrate obtained by fermentation under the conditions.

2. The process for high yield of humic acid by straw aerobic solid state fermentation according to claim 1, wherein fermentation is carried out under the optimal conditions obtained, and fermentation samples of 0, 5, 10, 16, 22, 29 and 36 days are respectively taken to carry out temperature, pH, TOC, TN and determination of contents of lignin, cellulose, hemicellulose and humic acid.

3. The process for producing humic acid with high yield by straw aerobic solid state fermentation according to claim 1 or 2, wherein the dominant microbial community in the humic acid fermentation process is obtained by high-throughput sequencing, wherein Pseudooxanthenas, Lactobacillus, Phenylobacterium, Pseudomonas, Brevundimonas, Rhizobium and Chryseobacterium are the dominant genera in the aerobic fermentation process.

Technical Field

The invention belongs to the technical field of biology, and particularly relates to a process for producing humic acid with high yield by straw aerobic solid state fermentation.

Background

The main components of the straw are lignin, cellulose and hemicellulose. Wherein cellulose is the highest content (about 30% -42%); secondly, hemicellulose (about 35-48 percent); lignin (about 15% -25%). Lignocellulose is difficult to degrade due to its special structure. The lignin wraps the cellulose and hemicellulose to form a dense network structure, so that the cellulase cannot contact the cellulose. Therefore, a great amount of straws are incinerated or piled for treatment every year, and resource waste is caused.

The Chinese has abundant straw resources. But the problems of relatively laggard straw treatment technology, low industrialization degree, high cost of effective utilization of straws and the like. Most of the straws are piled on the spot or directly burned, which causes great resource waste. Meanwhile, the burning of the straw also causes the emission of greenhouse gases, which causes the problems of air pollution, structural damage of soil components and the like. Therefore, the method for converting the straws into the products with application value is an effective method for solving the problems by reasonably and effectively utilizing the straw resources and using the process with low cost and high efficiency.

Aerobic composting fermentation of cellulose substrate, simple operation and low cost is an effective process for effectively solving straw waste. According to the temperature change in the aerobic composting process, the composting process can be divided into three stages, namely a medium temperature stage, a moderate temperature stage and a mature stage. The aerobic composting process is regulated by the action of various microorganisms, and the particle size, the ventilation quantity and the pretreatment of the fermentation substrate are main determinants for converting straws into humic acid by the microorganisms. Humic acid not only can promote the growth and metabolism of microorganisms, but also plays an important role in soil remediation. Therefore, the optimized process for obtaining the high-yield humic acid by the aerobic fermentation of the straws is an effective means for solving the waste of the straws.

Disclosure of Invention

Aiming at the problems, the invention researches the influence of different substrate particle sizes, ventilation quantities and cellulase addition quantities on the yield of humic acid and the degradation of organic matters of straws by taking crop straws as raw materials through aerobic fermentation, and obtains the optimized process conditions for producing the humic acid by the aerobic fermentation of the straws.

The invention provides application of humic acid produced by the process in the aspect of seed germination rate.

The invention also provides high-throughput sequencing analysis of microorganisms at different fermentation times, and discloses dominant bacteria in the fermentation process of humic acid.

In order to solve the technical problems, the invention adopts the following technical scheme:

a process for producing humic acid with high yield by straw aerobic solid state fermentation comprises the following steps:

1) crushing dried straw stalks, and screening a substrate with the substrate particle size of 0.2-12mm by using sieves with different meshes for later use; weighing 200-400g of sludge and materials with different substrate particle sizes, mixing and adding into a reactor; setting ventilation quantity at 0.1-0.9L/min and cellulase addition quantity at 5-20FPU/g substrate, respectively, and fermenting to obtain the optimal fermentation substrate with particle size of 0.5-1.0 mm;

2) respectively setting the ventilation quantity to be 0.1-0.9L/min and the cellulase addition quantity to be 5-20FPU/g substrate under the condition of the optimal fermentation substrate particle size, and fermenting under the condition to obtain the optimal ventilation quantity to be 0.5-0.8L/min;

3) under the conditions of the optimal fermentation substrate particle size and the optimal ventilation quantity, the addition amount of the cellulase is set to be 5-20FPU/g substrate, and the optimal cellulase addition amount is 10-15FPU/g substrate obtained by fermentation under the conditions.

Further, fermentation was carried out under the optimum conditions obtained above, and fermentation samples on days 0, 5, 10, 16, 22, 29, and 36 were taken for measurement of temperature, pH, TOC, TN, and contents of lignin, cellulose, hemicellulose, and humic acid, respectively.

Further, by high-throughput sequencing, a dominant microbial community in the humic acid fermentation process is obtained, wherein Pseudoxanthomonas, Lactobacillus, Phenylobacterium, Pseudomonas, Brevundimonas, Rhizobium and Chryseobacterium are dominant genera in the aerobic fermentation process.

Compared with the prior art, the invention has the following technical advantages:

1. the straw is used as a raw material to carry out aerobic solid state fermentation to produce humic acid, so that the utilization rate of the straw is improved.

2. The fermentation process parameters are optimized, and the straw resource conversion efficiency and the humic acid yield are improved.

3. The humic acid produced by fermentation is applied to the seed germination rate experiment, and the application value of the product is proved.

4. Discloses key microorganisms participating in the conversion of straws into humic acid.

Drawings

FIG. 1 is a graph showing the temperature change under optimum fermentation conditions;

FIG. 2 is a graph showing pH changes under optimal fermentation conditions;

FIG. 3 is a graph showing the variation of TOC, TN and C/N under optimum fermentation conditions;

FIG. 4 is a graph showing the change in humic acid production under optimum fermentation conditions;

FIG. 5 is a graph showing the change of microbial community in the aerobic fermentation process.

Detailed Description

The invention is described in further detail below with reference to the figures and the detailed description.