CN104004787B

CN104004787B - A kind of method of concentrating and separating biological flocculant from fermentation liquid

Info

Publication number: CN104004787B
Application number: CN201410230668.5A
Authority: CN
Inventors: 杨春平; 仇璐; 曾光明; 刘红玉; 张毅; 程燕; 何慧军; 严洲
Original assignee: Hunan University
Current assignee: Hunan University
Priority date: 2014-05-28
Filing date: 2014-05-28
Publication date: 2016-06-08
Anticipated expiration: 2034-05-28
Also published as: CN104004787A

Abstract

The present invention relates to a kind of method of concentrating and separating biological flocculant from fermentation liquid. The method utilizes biological flocculant active component prepared by the rhodococcus erythropolis distribution characteristics under different pH condition, makes flocculant be concentrated on thalline in the basic conditions, realizes separating of flocculant and fermentation liquid by isolating thalline. Fermentation liquid is prepared first with rhodococcus erythropolis; Secondly the pH with NaOH solution adjustment fermentation liquid is 10��11, stands 0.5��3h; The last centrifugal 10min when rotating speed is 3000��7000r/min, separates the flocculant obtaining concentrating in thalline. The method has the advantages such as simple, efficient, low stain, low cost, and strain can be made as the carrier of flocculant, makes solid granular product, it is simple to transport and storage.

Description

A kind of method of concentrating and separating biological flocculant from fermentation liquid

Technical field

The invention belongs to biological technical field, particularly relate to biological flocculant prepared by rhodococcus erythropolis distribution characteristics at various ph values, the method for concentrating and separating biological flocculant from its fermentation liquid.

Background technology

Present stage water pollution is serious, water resource worsening shortages, administers sewage and raising water resource recycling rate of waterused is extremely urgent. In the method for sewage disposal, flocculent precipitation is a kind of than more efficient, economic simple method. Biological flocculant be microorganism produce in growth and breeding process there is flocculation, special macromolecule metabolite solid suspended particle not degradable in liquid can be made to condense, precipitating, possess efficient, nontoxic, safety advantages of higher, be widely used in the fields such as wastewater treatment, drinking water treatment, fermentation industry and food industry. Kurane in 1986 et al. utilizes rhodococcus erythropolis (Rhodococcuserythropolis) to succeed in developing microbial flocculant NOC-1, is one of good biological flocculant of the flocculating effect being currently known. Guo Junyuan et al. utilizes the biological flocculant that pig farm breeding wastewater and residual actived sludge produce for rhodococcus erythropolis, can effectively process dyeing waste water, but flocculant still fails to efficiently separate out.

Biological flocculant is produce with the form of fermentation culture mostly, and it is mainly composed of the biomacromolecule Organic substances such as protein, polysaccharide, there is storage difficult, not readily transportable, it is difficult to carry out the defect of industrialized production. It is similar that the method for current biological flocculant separating-purifying proposes method to polysaccharide and protein, mostly based on gel electrophoresis, organic solvent extraction, alkali extraction method, also exist that separation efficiency is low, complex operation, flow process complicated, medicine consumption is big and easily cause the problem such as post processing environmental pollution of organic solvent, be unfavorable for practical application and the popularization of biological flocculant. Therefore it is badly in need of developing the process for separation and purification of the biological flocculant that can be suitably used for large-scale production of efficient convenient economy.

This method is based in above-mentioned insoluble problem a kind of new method of concentrating and separating biological flocculant from fermentation liquid put forward.In general, bacteriocin producing strains can adsorb bacteriocin molecule produced by it, and this absorption is that to have pH dependent. This method utilizes the active component of biological flocculant prepared by rhodococcus erythropolis distribution characteristics at various ph values, it is 10��11 by regulating the pH of the fermentation liquid having produced biological flocculant, first quickly stirring at a certain temperature, standing adsorption a period of time again, centrifugation supernatant and thalline subsequently, now major part biological flocculant concentrates on rhodococcus erythropolis thalline, thus realizing separating of flocculant and supernatant. This kind of method has simply, efficiently, pollution-free, low cost and other advantages, and strain can be made as the carrier of flocculant, makes graininess, it is simple to transport, stores, has great application prospect.

Summary of the invention

It is contemplated that propose a kind of method of concentrating and separating biological flocculant from fermentation liquid simple, efficient, free of contamination.

The method comprises the steps:

1) the rhodococcus erythropolis fermentation medium that initial pH is 6.5��8.5 is prepared, after autoclaving, the rhodococcus erythropolis seed liquor of inoculation 5%, in fermentation medium, shaking table shakes fermentation 60��80h, control temperature 25��30 DEG C, rotating speed 120��130r/min.

2) pH with the NaOH solution adjustment fermentation liquid of 1.0mol/L is 10��11, first quickly stir 3��5min, after under 3��6 DEG C of conditions stand 0.5��3h, it is 3000��7000r/min at rotating speed subsequently, when temperature is 4 DEG C, centrifugal 10min, separates the flocculant obtaining concentrating on thalline.

Accompanying drawing explanation

Fig. 1 is flocculant activity component distribution situation in strain and supernatant in different pH situations in example one fermentation liquid, and Fig. 2 is flocculant activity component distribution situation in strain and supernatant in different pH situations in example two fermentation liquid.

Detailed description of the invention

Below in conjunction with description specific embodiment, the present invention will be further described:

Embodiment one:

Prepare the fermentation medium of rhodococcus erythropolis: glucose 10g/L, yeast powder 2g/L, NaCl0.5g/L, magnesium sulfate 0.5g/L, K₂HPO₄2g/L, KH₂PO₄2g/L, initially its initial pH is 7.0. After autoclaving, being inoculated in fermentation medium by the inoculum concentration of 5%, concussion fermentation 72h on shaking table, controlling temperature is 30 DEG C, and rotating speed is 130r/min.

The pH regulating fermentation liquid by the NaOH solution of 1.0mol/L is 2��11, first quickly stirs 1min, rear standing adsorption 1h. It is 6000r/min at rotating speed subsequently, centrifugal 10min when temperature is 4 DEG C, separation of supernatant and strain, blank sample is measured respectively under 7230G visible spectrophotometer 550nm, add the optical density value of the aqueous suspension ofkaolin of fermented liquid supernatant liquid and thallus suspension liquid, utilize formula to calculate flocculating rate. Result is such as shown in Figure of description Fig. 1.

As shown in Figure 1, under strongly alkaline conditions, the flocculating rate of thallus suspension liquid, more than the flocculating rate of supernatant, illustrates that now flocculant mainly concentrates on thalline. As pH=11, the flocculating rate of thallus suspension liquid is 51.25%, and the flocculating rate of supernatant is 22.29%, can substantially realize separating of flocculant and supernatant. Utilizing this rule can regulate the pH value of fermentation liquid after fermenting for pH is 10��11 to realize the concentrating and separating of biological flocculant.

Embodiment two:

Prepare the fermentation medium of rhodococcus erythropolis: glucose 10g/L, yeast powder 0.5g/L, NaCl0.1g/L, magnesium sulfate 0.2g/L, K₂HPO₄5g/L, KH₂PO₄2g/L.Its initial pH initial is 9.5. After autoclaving, being inoculated in fermentation medium by the inoculum concentration of 5%, concussion fermentation 72h on shaking table, its temperature is 30 DEG C, and rotating speed is 130r/min.

The pH regulating fermentation liquid by the NaOH solution of 1.0mol/L is 2��11, first quickly stirs 1min, rear standing adsorption 1h. It is 6000r/min at rotating speed subsequently, centrifugal 10min when temperature is 4 DEG C, separation of supernatant and strain, blank sample is measured respectively under 7230G visible spectrophotometer 550nm, add the optical density value of the aqueous suspension ofkaolin of fermented liquid supernatant liquid and thallus suspension liquid, utilize formula to calculate flocculating rate. Result is such as shown in Figure of description Fig. 2.

As shown in Figure 2, as pH=10 or 11, the flocculating rate of thallus suspension liquid is more than the flocculating rate of supernatant, and as pH=11, the flocculating rate of thallus suspension liquid is 68.6%, and the flocculating rate of supernatant is only 8.54%, can substantially realize biological flocculant and separate with supernatant. The biological flocculant that in fermentation liquid, rhodococcus erythropolis produces is can be concentrated on thalline under 10��11 conditions at pH, it is achieved flocculant and separation of fermentative broth.

Claims

1. the method for concentrating and separating biological flocculant from fermentation liquid, it is characterized in that, utilize biological flocculant active component prepared by the rhodococcus erythropolis distribution characteristics under different pH condition, make major part biological flocculant active component in fermentation liquid be concentrated on rhodococcus erythropolis thalline when pH=10��11, centrifugation thalline and supernatant, thus realizing flocculant and separation of fermentative broth.

2. a method of claim 1, comprises the following steps:

1. preparation pH is the rhodococcus erythropolis fermentation medium of 6.5��8.5, and after autoclaving, the rhodococcus erythropolis seed liquor of inoculation 5%, in fermentation medium, stirs fermentation 60��80h, controls temperature 25��30 DEG C, rotating speed 120��130r/min;

2. regulating the pH of fermentation liquid by the NaOH solution of 1mol/L is 10��11, first quick stirring 3��5min, after under 3��6 DEG C of conditions, stand 0.5��3h, be 3000��7000r/min at rotating speed subsequently, centrifugal 10min, separate the flocculant obtaining concentrating in thalline.