CN101845459A

CN101845459A - Method for producing microbial flocculating agent

Info

Publication number: CN101845459A
Application number: CN 201010137960
Authority: CN
Inventors: 王兰; 赵璇; 唐静; 刘云洁
Original assignee: 南开大学
Priority date: 2010-04-02
Filing date: 2010-04-02
Publication date: 2010-09-29

Abstract

The invention discloses a method for producing a microbial flocculating agent, which belongs to the field of wastewater treatment. The method comprises the following steps of: 1) culturing and fixing Aspergillus souae strains into carriers; and 2) putting the carriers which are prepared in the step 1) and fixed with the strains into a three-phase fluidized bed reactor, adding a sterilized culture medium into the reactor, introducing sterile air into the reactor from the lower part of the reactor, discharging fermentation solution with high fermentation activity from the bottom of the reactor after the fermentation is finished, and leaving the immobilized strains in the reactor so as to finish first fermentation; and after the first products are discharged out of the reactor, adding the fresh sterile culture medium into the reactor from the upper part, namely entering the second fermentation, and then finishing multiple batches of fermentation in turn. The method continuously produces the microbial flocculating agent by adopting a new technique of microbial immobilization and selecting proper immobilized carriers, methods and fermentation processes; and the method can continuously produce 20 batches of microbial flocculating agent with high flocculating activity by using the same batch of immobilized strains in the three-phase fluidized bed reactor, improves the production efficiency by 4 to 6 times compared with a common method, lowers the cost, and is a new flocculating agent production process suitable for industrialized operation.

Description

A kind of production method of microbial flocculant

[technical field]:

The invention belongs to field of waste water treatment, be specifically related to a kind of production method of microbial flocculant.

[background technology]:

Water is origin of life, is human and the biology indispensable material of depending on for existence, also is the essential condition of industrial development.Along with rapid development of economy and Increase of population, the water consumption in China every year and quantity of wastewater effluent are also increasing, sewage and give water treatment problems increasingly serious.The development of water technology and engineering are used has become the necessary component of maintaining social economy's Sustainable development.

Flocculation technique is the main method that feedwater at present and wastewater treatment are adopted, and its effect depends primarily on the flocculation agent kind.On the flocculation technique development history, inorganic salts flocculation agent (as Tai-Ace S 150, iron(ic) chloride etc.) treatment effect is undesirable.And polymer-inorganic salt type flocculation agent (as polymerize aluminum chloride, bodied ferric sulfate etc.) is though treatment effect is good, and consumption is big, and environment is had secondary pollution.Can poison hydrobiont and microorganism as aluminum ion, by food chain and tap water, final harm humans health.And iron-based flocculating agent is corrosive to metal, and makes water that color be arranged, and this makes the application of aluminium and iron-based flocculating agent restricted greatly.Organic polymer coargulator such as PAM have that consumption is few, flocculation rate is fast, but residue is difficult for by biological degradation, and monomer whose has intensive neurotoxicity and " three cause " effect, cause secondary pollution, also will limit its application.Under this background condition, good, the wide accommodation of development flocculating effect, readily biodegradable, become inevitable to the biological flocculant of environment non-secondary pollution.Consider that from the environmental quality angle microbial flocculant can satisfy the stability and the security of its requirement; From the effect for the treatment of water and waste water, microbial flocculant satisfies the high efficiency of its requirement; From the complexity that realizes that industrialization is produced, the microbe species that can produce flocculation agent is many, and growth is fast, is easy to adopt the engineering means to realize industrialization.And the development along with industrialization is produced is expected to reduce production costs, thereby realizes low consumption.Flocculation agent is selected and " four property " principle of exploitation so microbial flocculant meets fully, is one of flocculation agent of current tool development prospect.Microbial flocculant is the class biomacromolecule material by microorganisms, can make other coagulation of materials precipitations, and itself have degradability, can solve the problem that security and contaminate environment aspect exist.Therefore will have a wide range of applications in fields such as food, fermentation industry, water treatments.

The still Screening for characteristics microbial flocculant that research both at home and abroad at present is more; Ambient conditions (comprising substratum nutritive ingredient, the initial pH of substratum, culture temperature, air flow etc.) is to the influence of microbial flocculant productive rate; The purification of microbial flocculant; The research of flocculation agent chemical constitution, physico-chemical property and flocculation mechanism; The relation research of bacterium for producing flocculant growth and microbial flocculant output and applied research etc.But research all is confined to laboratory scale mostly, and is very few to the industrialized preparing process and the application art research of flocculation agent, causes obstacle in industrial widespread use for it.

[summary of the invention]:

The purpose of this invention is to provide a kind of low cost, be fit to the flocculation agent production method that industrialization is operated.

The production method of microbial flocculant of the present invention comprises the steps:

1) bacterial classification Aspergillus souae (Aspergillus sojae is bought from DSMZ of Shanghai Institute of Pharmaceutical Industry) cultivation is fixed in the carrier;

2) carrier that is fixed with bacterial classification that step 1) is made is put into three-phase fluid bed reactor, the aseptic culture medium that adds sterilization, feed through the filtering sterile air of air filter from the bottom of reactor, the fermentation secondary fermentation liquid (having higher flocculation activity) that finishes is discharged from reactor bottom; Fresh aseptic culture medium adds from top, promptly enters second batch fermentation, and cyclical operation is successively used with a collection of seed and can be produced 18～20 batches of high flocculation activity flocculation agents.

The described culture of strains of step 1) is fixed, and substratum (m/v) is: NaNO ₃0.3～0.5%, KCl 0.05～0.1%, K ₂HPO ₄0.1～0.5%, FeSO ₄0.001～0.005%, MgSO ₄7H ₂O 0.05～0.1%, sucrose 4～6%; PH 5.5～6.5.

The described carrier of step 1) is the porous polyester particle, and diameter is 0.1～1cm.

The described bacterial strain fixed temperature of step 1) is 20～30 ℃, solid-to-liquid ratio 3～10g/L, and behind 100～200r/min shaking culture, 40～60h, thalline promptly is fixed in the carrier.

Step 2) described leavening temperature is 20～30 ℃, and yeast phase is 6～12h,

Step 2) sucrose concentration is 1～3% in the described substratum, and other compositions are with the substratum of step 1).

Reactor is a three-phase fluid bed reactor, and following ventilation, ventilation are into through the filtering sterile air of air filter, and air flow requires not tight, carrier is suspended get final product.

Advantage of the present invention and positively effect:

Process using of the present invention microbial immobilized new technology, select suitable fixation support and method and zymotechnique for use, carry out the serialization production of microbial flocculant, solved that present microbial flocculant production technique is backward, production cost is high, inefficient shortcoming, but this technology is used with 20 batches of the high flocculation activity microbial flocculants of a collection of immobilized bacterium continuous production in three-phase fluid bed reactor, and the production efficiency than ordinary process has improved 4～6 times, having reduced cost, is a kind of flocculation agent new process of production of suitable industrialization operation.

[description of drawings]:

Fig. 1 is reaction scheme figure of the present invention:

Annotate: (1) ... (20) expression can be fermented 20 batches with a collection of immobilized bacteria, enters second batch again after the fermented liquid that promptly last batch fermentation end has higher flocculation activity is discharged, and the like.

Fig. 2 is that the thalline of embodiment 1 is fixed in the image in the carrier.

[embodiment]:

Embodiment 1:

Utilize the porous polyester foam to be carrier, select carrier granule 0.5 * 0.5 * 0.5cm ³, solid-to-liquid ratio is 3g/L, behind 25 ℃, 100r/min shaking culture 50h, thalline promptly is fixed in (see figure 2) in the carrier, and can keep high activity the long period.

With the said fixing cell inoculation in three-phase fluid bed reactor, add fermention medium, controlled temperature is about 25 ℃, yeast phase 12h, can obtain having the fermented liquid of higher flocculation activity, after this batch fermentation liquid discharged from reactor bottom, fresh no bacteria fermentation culture medium adds from top, promptly enter second batch fermentation, and the like, reaction scheme is seen Fig. 1, experiment is this time produced 18 batches with a collection of seed, 18 batches of flocculation agent flocculating rate flocculation activity are all more than 90%, and the time of producing 18 batches of flocculation agent experience is 266 hours (comprising 50 hours immobilization time), and the free a collection of flocculation agent of the every production of bacterium generally needs 72 hours, produce 18 batches and need 18 * 72=1296 hour altogether, promptly by the immobilization operation, save the inoculation and the generation time of every batch of thalline, the production efficiency of this technology improves 4.87 times than common production technique efficient.

Embodiment 2:

The immobilization operation of bacterial classification is the same, leavening temperature is controlled at about 30 ℃, yeast phase 10h, other technological operation is the same, experiment is this time produced 20 batches with a collection of seed, 20 batches of flocculation agent flocculating rate flocculation activity are all more than 88%, the time of producing 20 batches of flocculation agent experience is 250 hours (comprising 50 hours immobilization time), and the free a collection of flocculation agent of the every production of bacterium generally needs 72 hours, produce 20 batches and need 18 * 72=1440 hour altogether, promptly by the immobilization operation, save the inoculation and the generation time of every batch of thalline, the production efficiency of this technology improves 5.76 times than common production technique efficient.

Claims

1. the production method of a microbial flocculant comprises the steps:

1) with bacterial classification Aspergillus souae, promptly Aspergillus sojae is bought from DSMZ of Shanghai Institute of Pharmaceutical Industry, cultivates to be fixed in the carrier;

2) carrier that is fixed with bacterial classification that step 1) is made is put into three-phase fluid bed reactor, adds the aseptic culture medium of sterilization, feeds through the filtering sterile air of air filter from the bottom of reactor, and the fermentation secondary fermentation liquid that finishes is discharged from reactor bottom; Fresh aseptic culture medium adds from top, promptly enters second batch fermentation, and the like, use with a collection of seed and can produce 18～20 batches of high flocculation activity flocculation agents.

2. the production method of microbial flocculant according to claim 1 is characterized in that, the described culture of strains of step 1) is fixed, and substratum (m/v) is: NaNO ₃0.3～0.5%, KCl 0.05～0.1%, K ₂HPO ₄0.1～0.5%, FeSO ₄0.001～0.005%, MgSO ₄7H ₂O 0.05～0.1%, sucrose 4～6%; PH 5.5～6.5.

3. the production method of microbial flocculant according to claim 1 is characterized in that, the described carrier of step 1) is the porous polyester particle, and diameter is 0.1～1cm.

4. the production method of microbial flocculant according to claim 1 is characterized in that, the described bacterial strain fixed temperature of step 1) is 20～30 ℃, solid-to-liquid ratio 3～10g/L, and behind 100～200r/min shaking culture, 40～60h, thalline promptly is fixed in the carrier.

5. the production method of microbial flocculant according to claim 1 is characterized in that step 2) described leavening temperature is 20～30 ℃, yeast phase is 6～12h.

6. the production method of microbial flocculant according to claim 1 is characterized in that step 2) sucrose concentration is 1～3% in the described substratum, other compositions are with the substratum of step 1).