JP5867911B2 - Method for producing ethanol from waste - Google Patents

Description

  The present invention relates to a method for producing ethanol from paper in waste by simultaneous saccharification and fermentation reaction.

  In recent years, according to statistics from the Ministry of the Environment, approximately half of the general waste that is incinerated is paper cloth, most of which is paper. These papers are papers that have not been put on a general recycling route as papers that are not suitable for recycling, but some papers that are discarded without being recycled are mixed. Papers that are not suitable for recycling include dirty paper, textured paper, paper processed with other plastics, and the like.

  It has been studied to take out such papers and use them as biomass resources (Patent Document 1) and to collect them in a pulp form.

  Since papers are mainly composed of plant-derived cellulose, they are a kind of biomass. The difference from other biomass is that the delignification treatment is performed during the papermaking process, and the purity of the cellulose component is relatively high. Therefore, when enzymatic saccharification treatment is performed, it is compared with other biomass. It can be said that processing is easy.

  In addition, when selecting a method that includes saccharification by an enzyme from among ethanol production methods that use biomass rich in cellulose as a raw material, the reaction should be carried out by a simultaneous saccharification and fermentation method that can suppress the effects of competitive inhibition by the product of the enzyme reaction. Is said to be useful. This is a method of simultaneously performing enzymatic saccharification of raw materials and utilization of sugar (ethanol production) by yeast, which is a fermentation microorganism, in one reaction tank. At present, the cost of saccharifying enzymes is high, so the simultaneous saccharification and fermentation method is useful for proceeding the reaction with a smaller amount of enzyme, but the reaction takes several days to efficiently perform the enzymatic saccharification. Is called.

JP 2002-159953 A

  Here, when ethanol is produced by using paper pulp extracted from general waste as a raw material and simultaneously saccharifying and fermenting it, the influence of various bacteria is feared in the reaction for several days.

  When the sugar solution is obtained by performing other treatments, for example, hydrolysis with pressurized hot water, acid hydrolysis with sulfuric acid, or both, in order to pass through a state that is significantly unsuitable for the survival of miscellaneous bacteria, Less likely to be affected by bacteria. Furthermore, when fermentation is performed using sugar solution as a raw material, the residence time is several hours, at most a dozen hours at the most. Therefore, even if various bacteria are present, the effect is considered when considered together with the growth rate of other microorganisms. In most cases, it is not affected by the ratio of the amount to the microorganism for fermentation.

  On the other hand, when transported with general waste and in contact with other wastes, the papers already have many germs when recovered as paper pulp. The presence of miscellaneous bacteria can also be a reaction, and thus has a significant effect. Therefore, a method for suppressing miscellaneous bacteria for using the raw material for ethanol production is required.

  The present invention has been made in consideration of the above circumstances, and can produce ethanol from general waste, which can suppress the adverse effects of various bacteria during the simultaneous saccharification and fermentation reaction using paper pulp extracted from general waste. It aims to provide a way to do.

  In order to solve the above-mentioned problems, the present inventors have conducted extensive research, and as a result, low-temperature heat treatment of the raw material containing paper pulp, and by using an antibiotic during the simultaneous saccharification and fermentation reaction, We have discovered a method that can achieve equivalent ethanol production efficiency.

  That is, the present invention collects paper in waste including waste paper as a paper pulp raw material, subjecting the paper pulp raw material to a low temperature heat treatment of 60 ° C. or more and less than 100 ° C., The temperature is lowered to a viable temperature range according to the fermenting microorganism used for fermentation, and then a simultaneous saccharification and fermentation reaction is performed on the low-temperature heat-treated product to simultaneously act the enzyme and the microorganism for fermentation, thereby producing ethanol. In the method for producing ethanol from waste, an antibiotic is added when the simultaneous saccharification and fermentation reaction is performed.

  Here, there are general waste and industrial waste that are subject to the Waste Disposal Law, and waste discharged from general households, offices discharged from offices, etc. as general waste Examples include garbage.

  Paper refers to paper contained in waste, and paper pulp refers to paper obtained after physical dehydration of the disaggregation liquid obtained by depulping (pulping) the paper in the waste with water. However, since the processing of the present invention can also be applied to waste paper for recycling and paper sludge, there is no particular limitation as long as it is a paper-derived raw material.

  The low temperature heat treatment is derived from the fact that a general sterilization treatment is a heat treatment at a low temperature with respect to 100 ° C. or higher at which steam sterilization can be performed. In the present invention, 60 ° C. or higher and lower than 100 ° C., more preferably 70 ° C. That's it.

  The low-temperature heat treatment may be performed at the time of pulping, which is the main process, out of a series of process steps that take paper from waste and use it as a raw material, or it is performed on slurry after pulping and pulp after dehydration. Further, heat treatment may be performed through these plural steps.

  It is desirable that the heat distribution during the heat treatment is uniform, and therefore mechanical stirring may be involved.

  The heat treatment time is desirably 2 hours or more after reaching the above predetermined temperature, and more desirably 4 hours or more. On the other hand, although it depends on the facility, it is desirable that the collection of general waste is carried out every day because of its processing efficiency. The treatment time of the low-temperature heat treatment in the present invention is not limited to the upper limit if there is an effect, but it is desirable that the treatment time be within 24 hours due to the above circumstances.

  Antibiotics used in simultaneous saccharification and fermentation using pulp after low-temperature heat treatment are generally called antibiotics. Antibiotics are desirable for substances having a broad antibacterial spectrum, desirably for substances having a low effective concentration, and desirably for substances that can be produced at low production costs, but are not particularly limited.

  Examples of such antibiotics include actinomycin, azithromycin, aspoxicillin, amphotericin, arbekacin, ampicillin, erythromycin, oxacillin, oxytetracycline, kanamycin, carbenicillin, clindamycin, chloramphenicol, chlortetracycline, gentamicin, gentamicin, cycloserine, Dihydrostreptomycin, streptomycin, spectinomycin, cephalosporin, cephalothin, cephalolzine, cefquinome, tylosin, tetracycline, nystatin, neomycin, virginiamycin, hygromycin, bacitracin, paromomycin, vancomycin, puromycin, blasticidin, bleomycin, penicillin, penicillin, penicillin , Mitomycin, mycophenolic acid, methicillin, lincomycin, and among these agents the derivatives and salts, at least one can be cited.

  The antibiotic exerts its activity by inhibiting biological reactions essential for maintaining vital activities such as growth and proliferation of microorganisms. It is known that its activity generally works for sterilization at a high concentration and works bacteriostatically at a low concentration, but in order to obtain the effects of the present invention, it is necessary to carry out simultaneous saccharification and fermentation reaction. It is required to work bacteriostatically to the extent that it does not adversely affect. Some antibiotics have sufficient activity even at 1 ppm or less, but considering that the antibiotic itself is decomposed, it is added so that it becomes 2 ppm or more with respect to the total weight of the simultaneous saccharification and fermentation reaction product. It is considered preferable. Moreover, if it is the density | concentration which acts bacteriostatically, it is desirable to add the said antibiotic at the time of the simultaneous saccharification and fermentation reaction considered to be before the absolute number of the miscellaneous bacteria which approached zero by low-temperature heat processing increases by proliferation.

  According to the present invention, it is possible to suppress the influence of miscellaneous bacteria derived from the contact of garbage other than paper waste with the paper waste in general waste on the simultaneous saccharification and fermentation reaction. As a result, the yield at the time of applying papers present in general waste that has only been incinerated to the raw material for simultaneous saccharification and fermentation reaction is improved, and a stable reaction can be realized. By improving the yield, the final ethanol concentration is improved, and not only the energy cost required for distillation is reduced, but also the proportion of the equipment cost can be reduced. As a result, it is possible to adjust the organic resources such as papers, which are abundant in general waste, to a state where they can be used as biofuel raw materials.

It is a graph which shows the comparison of the ethanol productivity in the low temperature heat processing of Example 1, and an autoclave process. It is a graph which shows the ethanol density | concentration at the time of completion | finish of simultaneous saccharification and fermentation reaction of Example 2. It is a graph which shows the density | concentration of the antibiotics by the photo recorder of Example 3, and a germ suppression effect. It is a graph which shows the kind of antibiotics by a photo recorder of Example 4, and a germ suppression effect.

  Hereinafter, the present invention will be specifically described based on examples and drawings.

  Papers extracted from the waste by manual sorting were pulped, and the pulp slurry that passed through a 5 mm screen was dehydrated with a screw press to prepare paper waste pulp. The moisture content of the paper pulp was approximately 60%. Examples 1 and 2 below were carried out using the obtained paper pulp, and Examples 3 and 4 were carried out using pulping water at the time of pulping.

(Example 1)
Three paper pulps were prepared by adding pulping water at the time of pulping and adjusting the slurry concentration to 5%, and each was heat-treated at 60 ° C., 80 ° C., and 92 ° C. for 6 hours.

  After heat treatment, the paper slurry was squeezed in a clean bench, and simultaneous saccharification and fermentation was performed using paper pulp adjusted to a concentration of 15%. The enzyme for saccharification was Accel Race, a cellulase made by Genencor, and the microorganism for fermentation was Saccharomyces cerevisiae yeast. At the start of the simultaneous saccharification and fermentation reaction, chloramphenicol was added as an antibiotic so as to be 5 ppm, and the mixture was sufficiently stirred to be uniform, followed by shaking culture at 40 ° C. and 150 rpm.

  Separately, as a control group, the autoclaved raw material was subjected to simultaneous saccharification and fermentation reaction under the same conditions.

  The result is shown in FIG.

  The ethanol concentration produced on the fifth day of the simultaneous saccharification and fermentation reaction was slightly lower when heat-treated at 60 ° C., but almost the same ethanol concentration was confirmed. The ethanol concentration comparable to that of autoclaving could be achieved by further low-temperature heat treatment.

(Example 2)
The relationship between the low temperature treatment and the treatment time shown in Example 1 was examined in more detail.

  Four 60% pulp raw materials prepared from waste, adjusted to a 20% slurry using pulping water, were prepared. For each, 60 ° C for 2 hours, 60 ° C for 4 hours, and 70 ° C for 2 hours. The treatment was carried out at 70 ° C. for 4 hours.

  Divide each of the above four into two parts, one with antibiotics (chloramphenicol) added to 5 ppm, the other without antibiotics, other enzyme species, enzyme amounts, The simultaneous saccharification and fermentation reaction was carried out under the same conditions as in Example 1 for the yeast species, yeast amount, temperature, and stirring.

  Separate saccharification and fermentation reactions were carried out for the autoclaved raw materials (positive control), those that were not treated with heat (negative control), and those that were only treated with antibiotics without heat treatment (drugs only). went.

  The reaction was completed in 5 days. Along with the ethanol concentration at the end, each reaction condition is shown in Table 1, and a graph of the final ethanol concentration is shown in FIG.

  When heat treatment and antibiotics were not added, the final ethanol concentration was 1.4%, and a clear decrease in production was observed. In other conditions, it was shown that ethanol concentration equivalent to complete sterilization (autoclave treatment) can be achieved by the combined use of heat treatment and antibiotic addition.

(Example 3)
0.1 mL of pulping water at the time of pulping is added to 5 mL of YPD medium (glucose concentration 5%) used for general yeast culture, 2-5 ppm of the antibiotic chloramphenicol is added, and the temperature is 65 ° C. BIO-PHOTORECORDER TVS062CA manufactured by ADVANTEC) was used to examine the growth of miscellaneous bacteria from the absorption of OD = 600. The pulping water is used at the time of pulp production, and has the same composition as the germs present in the pulp. As a result of culture observation, it was found that the generation of microorganisms was suppressed at 2 ppm or more.

Example 4
As in Example 3, 0.1 mL of pulping water at the time of pulping was added to 5 mL of YPD medium (glucose concentration 5%), and 5 ppm of ampicillin, chloramphenicol and streptomycin were added as antibiotics, and the photo recorder was brought to 50 ° C. Was used to examine the growth of miscellaneous bacteria from the absorption of OD = 600. As a result, suppression of microbial growth was confirmed.

Claims (4)

Paper in waste including waste paper is recovered as a raw material for pulp and paper, and only water or pulping water is added, and this is subjected to low temperature heat treatment at 60 ° C. or higher and lower than 100 ° C. for 4 to 24 hours. Simultaneous saccharification and fermentation in which the temperature of the heat-treated product is lowered to 40 to 50 ° C., which is a growth possible temperature range according to the fermentation microorganism used for fermentation, and then the enzyme and the microorganism for fermentation are allowed to act simultaneously on the low-temperature heat-treated product. In a method for producing ethanol from waste, by performing a reaction and thereby producing ethanol,
When performing the simultaneous saccharification and fermentation reaction, an antibiotic is added so that the concentration is 2 ppm or more with respect to the total weight of the simultaneous saccharification and fermentation reaction .
The antibiotics include arbekacin, ampicillin, oxacillin, kanamycin, chloramphenicol, gentamicin, dihydrostreptomycin, streptomycin, spectinomycin, cephalosporin, cephalothin, cephaloridine, cefquinome, neomycin, hygromycin and paromomycin, and these A method comprising one or more selected from the group consisting of derivatives and salts .   The method according to claim 1, wherein the temperature of the low-temperature heat treatment is a temperature of 70 ° C. or higher. The method according to claim 1 or 2, wherein the antibiotic comprises one or more selected from the group consisting of ampicillin, chloramphenicol and streptomycin .   The method according to any one of claims 1 to 3, wherein the antibiotic is added at the start of a simultaneous saccharification and fermentation reaction.

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