Process for producing a biofertilizer comprising the steps of solid-state fermentation, immobilization through allophane nanoparticles and a second fermentation; and the said biofertilizer

Abstract

Process for producing a biofertilizer, comprising the following steps: a) solid-state fermentation to produce enzymes and nutrients critical for plant nutrition; b) immobilization through allophane nanoparticles of the enzymes and substrates produced during stage a); and c) a second fermentation to favor the development of microorganisms that improve the quality of the biofertilizer. Protection is also sought for the biofertilizer that is produced from this process.

Claims

1. Process for producing a biofertilizer comprising the following stages: a) subjecting an agricultural, livestock and agro-industrial waste to a first solid-state fermentation (SSF) for producing organic substrates, microorganisms and enzymes selected from the group consisting of phosphatases, sulfatases, asparaginases and glutaminases; b) immobilizing the enzymes and substrates produced during stage a) by adding allophane nanoparticles, wherein the allophane nanoparticles are spherules having a diameter of 3-8 nm that form porous aggregates, to obtain an intermediate product, and protecting the enzymes and organic substrates from microbial degradation by the microorganisms; and c) subjecting the intermediate product obtained from stage b) to a second solid-state fermentation (SFF) to reduce the number of pathogenic microorganisms thereby improving the quality of the obtained biofertilizer which is innocuous to plants.

2. Process for producing a biofertilizer according to claim 1, wherein stage a) of the process is carried out in reactors or piles.

3. Process for producing a biofertilizer according to claim 1, wherein stage a) is carried out at a temperature of between 25 C. and 70 C., with a moisture level of between 55% and 80%, and lasts between 12 and 18 days when carried out in reactors and between 5 and 10 weeks when carried out in piles.

4. Process for producing a biofertilizer according to claim 1, wherein in stage b) allophane is added in a proportion of between 10% and 40% weight/weight with regard to a dry fermented matter.

5. Process for producing a biofertilizer according to claim 1, wherein the SSF stage c) lasts between 30 and 60 days and is carried out at a temperature of between 15 C. and 50 C., with a moisture level of between 60% and 85%.

6. The process for producing a biofertilizer according to claim 1, wherein the obtained biofertilizer has a concentration of encapsulated enzymes in the allophane comprising 1.09-4.4 IU/g of alkaline phosphatase, 0.2-1.2 IS/g of acid phosphatase, 0.05-0.1 IU/g of arylsulfatase, 0.6-1.05 IU/g of L-asparaginase, and 3.0-4.6 IU/g of L-glutaminase.

Description

DESCRIPTION OF THE INVENTION

(1) The invention consists of a process for producing a biofertilizer based on enzymes immobilized in a nanomaterial, making it possible to increase the availability of nutrients when required by plants.

(2) The first stage of the said process consists of a solid-state fermentation under conditions necessary for producing certain key enzymes for plant nutrition. Also produced during this fermentation are the substrates necessary for enzymes to catalyze the mineralization reactions necessary for providing plants with sufficient P, N, S and other elements. During the second stage of the process, the nanomaterial allophane is added to the fermentation product. This nanomaterial consists of Si and Al nanoparticles that form aggregates in which the enzymes produced during the SSF are immobilized, protecting them from microbial degradation and increasing their catalytic efficiency. The third stage consists of a second fermentation under conditions necessary for reducing the number of pathogenic microorganisms that may have survived the first stage, thus improving the quality of the fermentation product. The result of these processes is a fermentation product that has been enriched with enzymes, organic substrates, plant growth hormones, and micro and macro mineral nutrients necessary for plant growth.

(3) In the first stage, agricultural, livestock and agro-industrial waste is subjected to solid-state fermentation in either reactors or piles. Fermentation parameters are a temperature between 25 C. and 70 C. and moisture levels between 55% and 80%. This stage lasts between 12 and 18 days in reactors and 5 and 10 weeks in piles and promotes the production of enzymes such as phosphatases, sulfatases, asparaginases and glutaminases, in addition to organic substrates and beneficial microorganisms. The fact that pathogenic microorganismsespecially those associated with gastrointestinal diseases, such as E. coli and Salmonella sp.also multiply in this stage makes it necessary to carry out a second SSF during the final stage of the process.

(4) The duration of the SSF phase depends on whether fermentation is carried out in reactors or piles. In reactors, it is possible to observe a cyclical pattern where activity rises and decreases over a prolonged period, making a shorter fermentation necessary. On the other hand, the activity in piles after three months of SSFwhere temperatures of 70 C. are reachedis similar to the first peaks obtained from the reactors.

(5) At the end of the first stage the nanoparticles are added. These consist of allophane at a percentage of between 10% and 40% weight/weight (dry fermented matter vs. dry allophane matter). This stage enables the encapsulation of the enzymes and part of the previously generated substrates. A key aim in the creation of a biofertilizer is for it to be an efficient bio-catalyzer, for which it is important to immobilize the enzymes it contains. In this regard, these nanoparticles have an ideal surface area/volume ratio for serving as an enzymatic carrier. Allophane is a nanoparticle or nanoclay that allows a very high degree of enzymatic immobilization. It consists of spherules with a diameter of 3 nm to 8 nm that form porous aggregates, allowing for interaction with the organic matter and the physical protection of the enzymes in the said matter.

(6) During the third stage, a second and more prolonged SSF is carried out for 30 to 60 days at a temperature between 15 C. and 50 C. and with moisture levels between 60% and 85%. These conditions favor the development of processes that produce metabolites that control and eliminate pathogenic bacteria.

(7) The final product of this process is a biofertilizer containing:

(8) a) encapsulated enzymes, mainly phosphatases, sulfatases, asparaginases and glutaminases; b) organic substrates containing P, N and S; c) organic compounds beneficial for plant growth, such as hormones, fulvic acids and humic acids; d) micro-organisms beneficial for plant development.

(9) The biofertilizer has a concentration of organic matter of 55% to 70%, of allophane of 10% to 40%, and a concentration of encapsulated enzymes in the allophane of: 1.09 IU g.sup.1 to 4.4 IU g.sup.1 for alkaline phosphatase; 0.2 IU g.sup.1 to 1.2 IU g.sup.1 for acid phosphatase; 0.05 IU g.sup.1 to 0.10 IU g.sup.1 for arylsulfatase; 0.6 IU g.sup.1 to 1.05 IU g.sup.1 for L-asparaginase; and 3.0 IU g.sup.1 to 4.6 IU g.sup.1 for L-glutaminase.

(10) This biofertilizer contains a pool of nutrients stored organically that will be liberated through enzymatic action during plant development depending on the concentration of nutrients in the soil. These nutrients are presented in Table 1.

(11) TABLE-US-00001 TABLE 1 Nutrients available in the biofertilizer. Organic matter 64.37% Nitrates (NNO.sub.3) 55.80 mg/kg Ammonium (NNH.sub.4) 404.70 mg/kg Available nitrogen 460.40 mg/kg Phosphorus (P) 0.78% Potassium (K) 1.20% Calcium (Ca) 3.08% Magnesium (Mg) 0.30% Iron (Fe) 5600 ppm Manganese (Mn) 580 ppm Zinc (Zn) 360 ppm Copper (Cu) 80 ppm Boron (B) 62.27 mg/kg Total N 3.08% Na 0.51%

(12) The effectiveness of this biofertilizer is equal to or greater than that of chemical fertilizers but with a higher degree of efficiency and sustainability, as it enables the reutilization of waste and avoids unnecessary nutrient loss into the environment, due to the fact that only the nutrients necessary for the plant are released according to its requirements over time.

(13) Unlike compost that mainly adds organic substrates and fulvic and humic substances to soils, the biofertilizer also adds enzymes, enabling it to release nutrients from the organic substrates in sufficient quantities for plant development. In the first stage of the biofertilizer production process, i.e. the fermentation stage for producing enzymes, it is possible to produce large amounts of the said enzymes (Table 2), whereas no significant quantities of these enzymes have been detected in commercial compost products.

(14) TABLE-US-00002 TABLE 2 Amount of enzymes produced during fermentation. Enzyme production in IU/t of dry fermented matter Arylsulfatase 100000 Acid phosphatase 600000 Alkaline phosphatase 4000000 L-asparaginase 800000 L-glutaminase 2000000

(15) In summary, this new biofertilizer has in one formulation the advantages of both controlled-release mineral fertilizers, providing the plant with available nutrients gradually over time, and of compost, adding organic substrates, humic substances and beneficial microorganisms to soils.

APPLICATION EXAMPLES

Example 1: Biofertilizer Production Process

(16) The manure used for the SSF trials was collected from calf fattening stalls at the Agrcola Pullami farm in Coihueco in the Chilean Bo Bo Region.

(17) The process comprises three stages, which are described below:

(18) I. Solid-State Fermentation of Manure for Enzyme Production.

(19) Enzymatic activity was evaluated under different temperature and moisture conditions during the solid-state fermentation of bovine manure in order to optimize the enzyme production process.

(20) The effect of temperature on enzymatic activity during the solid-state fermentation of bovine manure was assessed at 25 C., 35 C. and 55 C.

(21) The reactors for the solid-state fermentation process were designed by adapting the system proposed by Grewal et al. (2006). This system makes it possible to control temperature and moisture conditions. The first trial was carried out at a temperature of 25 C. and with undried manure, i.e. with a moisture level of over 80%. For the second trial the temperature was 35% and the moisture was 60%, and for the third trial the temperature was 55 C. and the moisture was 60%.

(22) FIG. 1 shows the equipment used for the fermentation process. A reactor (5) was placed in an incubator (6), where the said reactor consisted of a cylindrical PVC tube 16 cm in diameter and 30 cm long with an approximate capacity of 4 L. The base of the cylinder was covered with a metal wire mesh with 11 mm holes in order to homogenize the incoming airflow. The mesh wire was supported on an acrylic disk. In order to ensure aerobic fermentation, the reactors were connected to an air line (3) provided by an external aeration system fed by a 2 HP compressor (1). The air fed into the reactor was treated, first with a vapor trap and subsequently with an air filter aimed at minimizing the oil content from the compressor motor. This ensured that the air was free of particles that could have affected the biological process and/or the measurement of enzymatic activity. A rotometer (2) regulated the airflow, which was adjusted to 100 ml/min. The air line was connected through a tube to a glass jar with distilled water (4), in which bubbling occurred in order to maintain stable moisture conditions in the bioreactors. In order to measure the temperature, a Data Logger (7) was used that functioned as a scanner with temperature sensor inputs (thermocouples) connected to a computer (8).

(23) Every seven days the manure in each reactor was turned. This consisted in mixing the manure in order to homogenize it. After each turning, a 50 g sample was taken from each reactor. These samples were used to determine physical, chemical and biochemical parameters.

(24) For the first fermentation trial, fresh manure from the animal fattening farm was used exactly as it was received, with 80% moisture, and fermented at 25 C. to simulate ambient temperature during spring, with three repetitions.

(25) For the second SSF trial, the bovine manure was treated to lower the moisture level to 60% and the effects of temperature on enzymatic activity were assessed. The temperatures used for the trial were 35 C. and 55 C., which correspond to the average temperatures reached during the mesophilic and thermophilic stages, respectively, of the compost process. Enzymatic activity was measured until repetitive behavior over time was observed, with cycles of increasing and decreasing activity. This trial was carried out over a period of 10 weeks.

(26) Acid and Alkaline Phosphatase Activity:

(27) Enzymatic activity was determined using a method adapted from the one proposed by Vuorinen (1993, 2000), consisting in weighing 0.25 g of sample and mixing it with 1.25 mL of 62.3 mM 4-nitrophenyl phosphate in an MUB solution pH 5.0 to determine acid phosphatase activity and pH 9.0 to determine alkaline phosphatase activity. The enzyme with the substrate was then incubated at 30 C. for 30 min. The mixture was then rapidly cooled in an ice bath and 3 mL of ice cold diethyl ether were added. The mixture was shaken for 60 min in a shaker refrigerated at 4 C. After shaking, 0.5 mL of the resulting solution were extracted and, for acid phosphatase, added to 40.5 mL of 0.5 M NaOH solution in a 10 mL volumetric flask. For alkaline phosphatase, 1 mL of the solution already containing 4.5 mL of 0.5 M NaOH solution were dissolved in 2 mL of distilled water and shaken vigorously. Absorbance at 420 nm was then measured for the previously obtained extract using a spectrophotometer. A calibration curve was carried out to calculate the concentration of the product (p-nitrophenol) in the sample. Activity was expressed as IU g.sup.1 of dry fermentation product (international units in function of the dry fermented matter).

(28) The activity curves of both enzymes at different reactor temperatures are shown in FIG. 2 for alkaline phosphatase and FIG. 3 for acid phosphatase.

(29) In the SSF at 25 C. and 80% moisture, the highest alkaline phosphatase activity levels were reached in week 9 of the trial, with a value of 3.40 IU g.sup.1 of dry fermented matter, followed by week 4 with a value of 3.36 IU g.sup.1 of dry fermented matter, as seen in FIG. 2. The highest acid phosphatase levels were reached during week 7 of the trial, with a value of 1.02 IU g.sup.1 of dry fermented matter, followed by 0.98 IU g.sup.1 of dry fermented matter in week 5 and 0.93 IU g.sup.1 of dry fermented matter in week 6, as seen in FIG. 3.

(30) For alkaline phosphatase, the values obtained in the trial at 25 C. and 80% moisture were higher than those expected, considering that in similar studies the highest enzymatic activity of hydrolase enzymes has been associated with higher temperatures that are reached naturally during the composting process (Vuorinen, 2000; Mondini et al., 2004). Regarding acid phosphatase, as with results obtained for alkaline phosphatase, a cyclical behavior for the enzymatic activity during SSF was observed, with high values of acid phosphatase activity in weeks 7, 5 and 6.

(31) In the SSF carried out with 60% moisture, the evolution over time of the mixtures at 35 C. and 55 C. was characterized by a marked increase in alkaline phosphatase activity in week 3 of the trial, with values of 4.39 IU g.sup.1 of dry fermented matter and 2.44 IU g.sup.1 of dry fermented matter, respectively. Acid phosphatase activity increased in weeks 5 and 9 of the trial, with values of 1.22 IU g.sup.1 of dry fermented matter at 35 C. and 0.24 IU g.sup.1 of dry fermented matter at 55 C. In both cases, the values obtained at 55 C. were lower.

(32) Arylsulfatase Activity:

(33) The methodology for determining enzymatic activity described by Gonzalez et al. (2003) and Fornasier et al. (2002) was adapted, the hydrolytic action of the enzyme being applied to an artificial substrate (p-nitrophenyl sulfate, pNPS) in order to detect the product (p-nitrophenol, pNP) using spectrophotometry at 420 nm. The amount of enzymatic activity was thus proportional to the concentration of pNP in the medium after hydrolysis. 0.25 g of fermented matter were weighed and 5 mL of acetate buffer pH 5.7 and 1.25 mL of 5 mM pNPS in a buffer solution were added, and the mixture was incubated for 1 h at 37 C. After incubation, the mixture was cooled at 4 C. and 3 mL of diethyl ether were added. The mixture was then shaken at 200 RPM for 1 h, and 0.5 mL of the supernatant were taken with 2.5 mL of 1 M NaOH and absorbance was determined at 420 nm. Enzymatic activity in the sample was quantified through comparison with a curve based on the reference solution (fermented matter without substrate).

(34) As shown in FIG. 4, a high level of arylsulfatase activity was recorded in week 5 of the trial at 25 C. and 80% moisture, with a value of 0.1094 IU g.sup.1 of dry fermented matter, whereas the lowest level of activity for this trial was recorded in week 1, with a value of 0.0569 IU g.sup.1 of dry fermented matter. The highest level of arylsulfatase activity for the trial with 60% moisture and a temperature of 35 C. was reached in week 2, with a value of 0.1038 IU g.sup.1 of dry fermented matter, whereas the lowest level of activity was observed in week 5 with a value of 0.0058 IU g.sup.1 of dry fermented matter at a temperature of 55 C.

(35) Studies on arylsulfatase activity are especially rare with regard to composting and fermentation processes (Cayuela et al. 2008). Tejeda et al. (2009) detected a maximum arylsulfatase activity level of 0.0078 IU/g during week 2 of the composting process with temperatures close to those of the mesophilic stage and 52.8% moisture, the said value being much lower than those obtained in the present study. Similarly, in a composting study with waste from olive oil mills, Cayuela et al. (2007) describe a maximum arylsulfatase activity level of 0.0156 IU/g after 34 weeks, at the end of a composting process with 40%-60% moisture. Mondini et al. (2004), observed maximum arylsulfatase activity levels of 0.0335 IU/g after 85 days with garden and cotton waste. It is important to note, however, that the aim of these studies was to characterize stabilized or mature compost after the degradation process, whereas the present study was carried out on an SSF as such, with high moisture levels, constant temperatures and lower temperatures.

(36) L-Asparaginase and L-Glutaminase Activity:

(37) The methodology used was based on two procedures: the first was described by Frankenberger and Tabatai (1991a, 1991b) and Keeney and Nelson (1982) for the enzyme-substrate reaction stage; and the second involved the use of ammonium ion-selective equipment with a gas membrane, the principle of which is based on the transformation of ammonium ions to ammonia at a pH greater than 11. A fermentation sample of 0.5 g was mixed with 10 mL of Tris buffer pH 10 and 1 mL of substrate (0.5 mol/L asparagine or 0.5 mol/L glutamine). As a control, 0.5 g of fermentate with 9 mL of Tris buffer pH 10 were used together with 1 mL of substrate to which 35 mL of Ag.sub.2SO.sub.4KCl were added before the incubation process. The blank tubes were the same as the samples and the control tubes, but no substrate was added. All samples, with their corresponding blank and control tubes, were incubated for 2 h at 37 C. After incubation and, as with the control, 35 mL of Ag.sub.2SO.sub.4KCl were added to the samples to stop the reaction. The samples were subsequently filtered and the NH.sub.3 was distilled via steam distillation and trapped in boric acid (Sadzawka et al., 2005). Once the different samples had been distilled, they were titrated with 0.005 M sulfuric acid (H.sub.2SO.sub.4). The amount of sulfuric acid consumed was proportional to the concentration of ammonium and represented the liberation of the product generated by the enzyme.

(38) The L-asparaginase activity levels were higher with fermentation at 25 C. and 80% moisture than under the other conditions tested, reaching a value of 1.03 IU g.sup.1 of dry fermented matter in week 9 of the trial. In the fermentation trial at 35 C. and 55 C. with 60% moisture, the highest activity levels were recorded in weeks 7 and 6, respectively, with a visible increase in activity of the enzyme at 55 C. starting in week 6, as seen in FIG. 5. The almost non-existent difference between maximum activity levels reached at 25 C. and 55 C. confirms the wide temperature range in which the enzyme functions. This is described by El-Bessoumy et al. (2004), who state that, although L-asparaginase reaches maximum activity levels at 37 C., activity remains at 52% at 50 C.

(39) L-glutaminase was significant in reaching the highest activity levels of all enzymes tested. Under fermentation at 25 C., a maximum of 4.6 IU g.sup.1 of dry fermented matter was reached in weeks 5 and 10, whereas at 35 C. and 55 C. the highest activity level was reached at 35 C. during the first 5 weeks of fermentation, but with levels lower than those reached at 25 C. (FIG. 6).

(40) These results make it possible to determine optimal fermentation conditions for obtaining a preparation with the correct enzymes to meet the specific requirements of a soil. In the case, for example, of producing a biofertilizer where high activity of the enzyme alkaline phosphatase is desired, the said enzyme can be obtained in 3 weeks of manure fermentation at a temperature of 35 C. and with 60% moisture. On the other hand, if a mixture with high activity of the enzyme L-glutaminase is desired, fermentation must be carried out at 25 C., with 80% moisture and for no more than 5 weeks. It is thus possible to obtain high levels of enzymatic activity from a low-cost and abundant substrate such as manure. In addition, it is not always necessary to treat the manure before fermentation to adjust moisture.

(41) Solid-State Fermentation in Piles:

(42) The piles of bovine manure for enzyme production had a minimum volume of 1 m.sup.3. In this case, 2 piles with the dimensions 3 m2.5 m1 m (length, height and width, respectively) were used to evaluate 2 different SSF configurations. The first pile was thermally insulated with black polyethylene mesh filled with wheat straw, whereas the second pile was left exposed. Enzymatic activity was measured in samples obtained directly from the piles after SSF, as well as enzymatic activity under storage conditions at ambient temperature and 4 C.

(43) The manure was obtained from dairy cow stalls at the Humn Experimental Station of the Agriculture and Livestock Research Institute (INIA) in the Los ngeles area in Chile. Approximately 2 t were collected in a roofed area over a period of 3 days and subsequently transported to the El Nogal Experimental Station of the Faculty of Agronomy of the University of Concepcin, where the manure was spread out over a polyethylene surface for drying until a moisture level of 60% was reached. Then, two piles with the dimensions 3 m2.5 m1 m (length, height and width, respectively) were created, one of which was covered with mesh and straw insulation. The piles were turned 4 times a day to control temperature and watered with the same frequency to maintain a moisture level of 60%. After 9 days, 4 piles were created from the 2 initial piles in order to carry out the SSF. After 30 days of SSF the matter was placed in sacks (Table 3).

(44) TABLE-US-00003 TABLE 3 Sampling during SSF. Days After Description SSF Start First sampling to measure enzymatic activity from SSF 40 piles Storage in sacks at 4 C. and ambient temperature 58 Second sampling to measure enzymatic activity from stored 58 sacks

(45) FIG. 7 shows the activity of the different enzymes: alkaline phosphatase (a), acid phosphatase (b), and arylsulfatase (c) after solid-state fermentation under an insulating cover compared with enzymatic activity in a fermentation pile without insulation. It is possible to observe a tendency towards higher activity in the covered pile in this case. FIG. 8 shows the activity levels of the different enzymes: alkaline phosphatase (a), acid phosphatase (b), and arylsulfatase (c) from the insulated pile (black) and from the exposed pile (gray) after being stored for 37 days. The storage conditions are: 1) in sacks at 4 C., and 2) in sacks at ambient temperature. The results show that the fermentate from the insulated pile stored at 4 C. had significantly higher activity levels than the other samples. Stored in a warehouse, enzymatic activity decreases mainly due to the loss of moisture of the fermented matter. However, this process can be reverted by adding water to the product, as seen in FIG. 9.

(46) II. Addition of Allophane to a Manure Fermentate to Obtain a Biofertilizer

(47) The allophane used for this study consisted of spherules with a diameter of 5 nm.

(48) The aim of this trial was to optimize the enzyme immobilization process with allophane by determining the correct allophane/manure proportion for the highest level of enzymatic activity, as well as the ideal moment for adding the allophane and immobilizing the enzymes.

(49) The manure used was collected from calf fattening stalls and stored in a barn for at least 1 month. Subsequently, the manure was dried and treated by wetting it and shredding it with a chipping machine, after which it was stored at ambient temperature for 2 weeks. Before the trial began, the moisture level of the manure was brought up to 60%.

(50) The trial consisted of 2 treatments and 3 replicates for each one. All treatments were fermented for 16 days at 35 C. and with 65% moisture, except for treatment 1, corresponding to the unfermented manure. To carry out fermentation, an incubation chamber with controlled conditions was used. Allophane was added to each experimental unit in a proportion of 15% to 30% of dry matter at the end of the fermentation process (after 16 days). Unfermented manure without allophane was used as a control.

(51) Table 4 shows the conditions analyzed, where the allophane content corresponds to 11% on a wet basis. It is important to note that the enzymatic concentration is different for each of the three manure mixtures, as the enzymes come from the manure itself.

(52) TABLE-US-00004 TABLE 4 Experimental conditions for the trial. Addition of Manure Allophane Allophane/manure allophane (dry solid in (dry solid in proportion (days) grams) grams) 0/100 Manure 525 0 Control 525 0 15/85 16 446.25 78.75 30/70 16 367.5 157.5

(53) The enzymatic activity of the fermentates with 15% and 30% allophane was analyzed and compared with the activity in the manure and fermentate without allophane. The activity of the different enzymes was tested in the fermented matter obtained, to which two different proportions of allophane were added. In summary, enzymatic activity was measured in unfermented manure (F), fermented manure without allophane (s/A), and in the fermented manure with allophane added after 16 days, at the end of the SSF process. According to the results in FIG. 10, where the acid phosphatase activity levels are shown, there were no significant differences between the 15/85 and 30/70 allophane/fermentate mixtures. From a financial point of view, it is therefore advisable to work with a proportion of 15% allophane to 85% of fermented matter.

(54) III. Second Solid-State Fermentation for Maturing the Fermentate.

(55) The second solid-state fermentation is carried out to reduce the number of pathogens and obtain a biofertilizer that is innocuous to plants and safe to use. As shown in Table 4, this process enables a significant reduction of E. coli levels in the fermented matter.

(56) In order to determine the amount of pathogens present at the different stages of the biofertilizer production process, samples were taken throughout the process, as described below: a) Bovine manure fermentate, fermented for 17 days at 35 C. and with 65% moisture in a reactor. Sample taken from stage 1. b) Bovine manure fermentate, fermented in an exposed pile for 90 days. Sample taken from stage 1. c) Mature fermentate from pile SSF. Sample taken from stage 3 of the process.

(57) Salmonella sp. levels were determined using the most-probable-number method. Thus, 100 g, 10 g and 1 g samples were taken from the different fermentate samples using sterile bags and enriched with lactose broth, homogenized with a Stomacher and incubated for 24 h at 35 C. The mixtures were then transferred to a Rappaport-Vassiliadis selective medium for Salmonella spp. and incubated for 24 h at 35 C. Tubes with any degree of turbidity were transferred to SS Agar dishes and incubated again for 24 h at 35 C. Suspected Salmonella colonies (non-lactose fermenting, H.sub.2S producing) were verified using the Remel RapID ONE System.

(58) For the E. coli count, 25 g samples of each fermentate type were prepared, added to 225 mL of diluent and homogenized in a Stomacher. For culturing, different dilutions of the preparation were inoculated in ChromoCult Coliform Agar ES. Suspected colonies were then confirmed using biochemical tests (TSI, LIA, MIO, urea and citrate).

(59) The results of the counts are shown in Table 5, where it can be seen that the E. coli levels decreased in fermentate c.

(60) TABLE-US-00005 TABLE 5 Pathogenic bacteria count. Salmonella count E. coli count STAGE (MPN g1) (CFU g1) Fermentate a <0.3 6160000 Fermentate b <0.3 143000000 Fermentate c <3 210

Example 2: Effect of the Biofertilizer on a Perennial Ryegrass (Lolium perenne L.) Crop

(61) The effects of the biofertilizer formulation on the yield of Lolium perenne L. (perennial ryegrass) were evaluated with regard to germination percentage, height of the young plants and dry matter yield.

(62) Germination Test:

(63) As a first step, a trial was carried out to evaluate the effects of the biofertilizer on 7-day-old perennial ryegrass seedlings. Perennial ryegrass seeds were pre-germinated and transplanted after 7 days to pots containing the biofertilizer and control pots containing commercial compost (Vita Frut produced by Rosario S. A.). The plants were watered with distilled water and no additional fertilizers were added. Plant development was recorded for 1 week. The results in FIG. 11 show that the plants that were transplanted to commercial compost presented higher mortality rates and lower development levels compared to the plants treated with the new biofertilizer.

(64) For step 2, the germination percentage of plants grown in a soil to which the biofertilizer had been added was measured and compared with the results obtained from germinating the perennial ryegrass seeds in an untreated soil with low nutrient content (control soil, Table 6), and a soil that was fertilized traditionally with a mineral product. As seen in FIG. 12, the germination percentage was higher when using the biofertilizer, whereas the soil that was fertilized traditionally had a lower germination percentage than the control soil (possibly indicating a degree of sensitivity on the part of the seed to mineral fertilizers). Different letters indicate significant differences in the averages of each treatment (t-test, p<0.05).

(65) TABLE-US-00006 TABLE 6 Chemical characterization of the control soil. NNO.sub.3 NNH.sub.4 S P EC ppm ppm ppm ppm OM % pH* dS/m 1.12 3.08 2.42 MB 6 B 2.66 5.88 0.037 S/R
Plant Development Trial:

(66) The bovine manure fermentate used was prepared in a controlled process lasting 2 weeks at 35 C. and with 60% wet basis moisture.

(67) The trial was carried out in an incubation chamber under the following conditions: photoperiod of 16 hours of light, with a temperature of 22 C. during the day and 15.5 C. at night.

(68) Pots with a diameter of 15 cm were used as experimental units. These were filled with 1.5 kg of low-nutrient soil (Table 6), which was sieved to 2 mm. To each experimental unit, a dose equivalent to 7 t ha.sup.1 of either biofertilizer or inorganic fertilizer with nutrient concentrations identical to the biofertilizer was added. There was also a control to which no fertilizer was added. In the case of the inorganic fertilizer, N was applied as urea, P as triple super phosphate, and K as potassium chloride. Table 7 presents the treatments and their composition. 120 seeds of Lolium perenne L. (Grasslands Nui) were sown in each experimental unit. Once the seedlings emerged, the units were thinned in order to leave 100 seedlings per unit. The experimental design was random blocks with 3 replicates.

(69) TABLE-US-00007 TABLE 7 Composition of each fertilizer treatment. Treatment Nutrient dose Fertilization Control 0 Biofertilizer 56.317 kg N/ha 7 t biofertilizer/ha 54.6 kg P/ha 84 kg K/ha Inorganic 56.317 kg N/ha 122.428 kg urea/ha fertilizer 54.6 kg P/ha 271.813 kg TSP/ha 84 kg K/ha 168 kg KCl/ha

(70) 15 days after the seeds had germinated, the height of the plants was measured. As seen in FIG. 13, the plants treated with the biofertilizer were taller than those of the control and inorganic fertilizer treatments. In addition, and contrary to expectations, the plants treated with the mineral fertilizer were not significantly different from those of the control.

(71) After two months of growth, the yield in dry matter was measured for each treatment. According to the results, the plants treated with the biofertilizer gave a higher yield of dry matter compared to the control and mineral fertilizer treatments (FIG. 14).