阅读说明：本技术 由发酵的固体催化的生产酯和生物润滑剂的方法 (Process for the production of esters and biolubricants catalysed by fermented solids ) 是由 J·A·卡瓦坎蒂达席尔瓦 G·B·圭拉 D·M·吉马良斯弗莱雷 E·C·冈卡维斯圭亚那 E· 于 2018-10-11 设计创作，主要内容包括：本发明涉及一种生产酯的方法,其包括在生物催化剂存在下使甲基生物柴油或游离脂肪酸与多羟基化醇反应,该生物催化剂是含有通过固态发酵在农业废料上培养微生物而产生的米黑根毛霉脂肪酶的发酵的固体。(The present invention relates to a method for producing an ester, which comprises reacting methyl biodiesel or free fatty acids with a polyhydroxylated alcohol in the presence of a biocatalyst, which is a fermented solid containing Rhizomucor miehei lipase produced by culturing microorganisms on agricultural waste by solid state fermentation.)

1. A process for producing an ester, characterized in that the process comprises reacting methyl biodiesel or free fatty acids with a polyhydroxylated alcohol in the presence of a biocatalyst, wherein the biocatalyst is a fermented solid produced by culturing a microorganism on agricultural waste by solid state fermentation.

2. Process according to claim 1, characterized in that the reaction of the methyl biodiesel with the polyhydroxylated alcohol is a transesterification reaction.

3. Process according to claim 1, characterized in that the reaction of the free fatty acids with the polyhydroxylated alcohols is a hydroesterification reaction.

4. A process according to claim 1 or 2, characterized in that the biodiesel is soy biodiesel or castor oil biodiesel.

5. A process according to any one of claims 1 to 4, characterized in that the biocatalyst is used in a concentration of 10 to 30% by weight.

6. Process according to any one of claims 1 to 5, characterized in that a molar ratio of alcohol to methyl biodiesel or free fatty acids of 2:1 to 5:1 is used.

7. Process according to claim 1, characterized in that the free fatty acids are obtained by reacting soybean oil or castor oil with a biocatalyst.

8. Process according to claim 7, characterized in that the biocatalyst is one or more commercial lipases or one or more lipases obtained from dormant castor beans.

9. A process according to any one of claims 1 to 8, characterised in that the polyhydroxylated alcohol is neopentyl glycol, trimethylolpropane or pentaerythritol.

10. Method according to any one of claims 1 to 9, characterized in that the microorganism is a fungus.

11. The method according to claim 10, characterized in that the fungus is Rhizomucor miehei (Rhizomucor miehei).

12. A method according to any one of claims 1 to 11, characterised in that the agricultural waste is cottonseed cake or palm oil cake.

13. Process according to any one of claims 1 to 12, characterized in that the fermented solid is added to the reaction in the form of a lyophilisate.

14. Process according to any one of claims 1 to 13, characterized in that the fermented solids are reused at least once.

15. Process according to any one of claims 1 to 14, characterized in that it additionally comprises a step of purifying the ester produced.

16. Use of an ester produced by the process as defined in any one of claims 1 to 15, characterized in that the ester is used as a bio-lubricant.

17. A biolubricant characterised in that it comprises an ester produced by a process as defined in any one of claims 1 to 15.

Technical Field

The present invention relates to the field of biocatalysis. More specifically, the present invention relates to the development of a new biocatalytic route that extends the possibility of obtaining esters that can be used as biolubricants by enzymatic routes.

Background

Base oils are the major constituent of lubricating oils and can be classified as mineral (obtained by distillation and refining of petroleum) and synthetic (obtained on the basis of chemical reactions of materials coming from the petrochemical industry.) although only a small portion of petroleum is consumed in the production of lubricants, a high percentage of these products is not properly discarded and therefore constitutes a threat to the environment⁶And (5) lifting water.

Increasingly stringent requirements imposed by environmental legislation, as enforced by european standard EN 13432, the demand in certain countries for food-grade lubricants for industry in this field and the problem of limited availability of petrochemical resources have helped to develop products derived from alternative sources and constitute one of the main priorities in the field of petrochemistry.

Biolubricants are biodegradable lubricants which can be broken down by microbial action and are generally obtained from vegetable oils modified by chemical reactions and used in applications where the possibility of leakage can jeopardize the environment.

Generally, biodegradability refers to the tendency of a lubricant to be metabolized by microorganisms for a period of up to one year. The form in which the microorganisms cause decomposition depends essentially on their structure. Vegetable oils are typically 99% biodegradable, usually falling to 90% -98% after mixing with additives.

The main types of esters used as biolubricants are diesters, phthalates, trimellitates, C36 dimers and polyol esters. Polyol esters are produced in the reaction between a polyol and a monocarboxylic or dicarboxylic acid. Such products offer unusual stability due to the absence of para-hydrogen in the beta position and the presence of a central quaternary carbon atom.

The reactions employed in the production of esters useful as biolubricants catalyzed by chemical catalysts are known in the art.

Document BR1020130335827 describes the production of a biolubricant based on the exchange reaction of biodiesel from castor oil with trimethylolpropane esters catalyzed by dibutyltin dilaurate (DBTDL). It should be noted that the reaction conditions are severe when DBTDL is used, requiring temperatures between 168 ℃ and 172 ℃ and vacuum.

Enzymatic or biological catalysts offer various advantages over chemical catalysts. These advantages include, for example, high selectivity of enzymes to their substrates, high yield, milder reaction conditions such as temperature and pressure, no degradation of the equipment, and biodegradability of the biocatalyst.

However, the high cost of commercially available enzyme preparations has been an obstacle to their economic viability for industrial application in the synthesis of low value-added and high-volume-sold products.

The use of enzymes in the solid form of a fermentation produced by solid state fermentation represents an alternative to reducing production costs, since the enzyme extraction and purification steps are eliminated.

Patent document PI0704791-6 relates to a process for synthesizing esters for use as biodiesel, which employs a reaction catalyzed by a fermented, solid-form lipase produced by the solid state fermentation of the bacterium Burkholderia cepacia (Burkholderia cepacian).

In the process of said prior art document, a fatty acid (in the case of an esterification reaction) or a triglyceride source (in the case of a transesterification reaction) is reacted with a monohydroxylated alcohol, which is preferably ethanol. This document does not envisage transesterification and hydroesterification reactions with polyhydroxylated alcohols, except for the use of enzymes of bacterial origin.

To date, it can be concluded that there has not been described in the prior art a method for obtaining biolubricant esters using transesterification and hydroesterification reactions with polyhydroxylated alcohols catalyzed by fermented solids obtained by culturing microorganisms on agricultural waste.

The present invention includes the use of low cost lipases, which facilitate the utilization of biomass and the economic feasibility of producing biolubricants by enzymatic routes.

Summary of The Invention

It is an object of the present invention to provide a process for producing esters which solves the above-mentioned main problems of the prior art.

To achieve the object, the present invention provides a method for producing an ester, which comprises reacting methyl biodiesel or Free Fatty Acids (FFA) with polyhydroxylated alcohols in the presence of a biocatalyst, wherein the biocatalyst is a fermented solid produced by culturing microorganisms in agricultural waste by solid state fermentation.

Another object of the invention relates to the use of the produced esters as biolubricants.

Another object of the invention relates to a biolubricant comprising the ester produced by the process of the invention.

Drawings

Fig. 1 shows the synthesis of a bio-lubricant based on the reaction between soy biodiesel and neopentyl glycol catalyzed by rhizomucor miehei (r.miehei) lipase present in the fermented solids of palm oil cake.

Fig. 2 shows the re-use of the fermented solids of palm oil cake in the synthesis of a bio-lubricant based on the reaction between soybean biodiesel and neopentyl glycol.

Fig. 3 shows the synthesis of a bio-lubricant based on the reaction between castor oil biodiesel and trimethylolpropane catalyzed by rhizomucor miehei (r. miehei) lipase present in the fermented solids of palm oil cake.

Fig. 4 shows the synthesis of a bio-lubricant based on the reaction between castor oil biodiesel and neopentyl glycol catalyzed by rhizomucor miehei (r.miehei) lipase present in the fermented solids of cottonseed oil cake.

Fig. 5 shows the synthesis of a bio-lubricant based on the reaction between free fatty acids of castor oil and neopentyl glycol catalyzed by rhizomucor miehei (r.miehei) lipase present in the fermented solids of cottonseed oil cake.

Fig. 6 shows the synthesis of a bio-lubricant based on the reaction between free fatty acids of soybean and neopentyl glycol catalyzed by rhizomucor miehei (r.miehei) lipase present in the fermented solids of cottonseed oil cake.

Fig. 7 shows the activity of the fermented solids of palm oil cake (SEP) after several re-uses without solvent washing in the bio-lubricant synthesis.

Detailed Description

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the subject matter of this invention belongs. The terminology used in the description of the invention has been for the purpose of describing particular embodiments only and is not intended to limit the scope of the teachings. Unless otherwise indicated, all numbers expressing quantities, percentages and proportions, and other numerical values used in the specification and claims, are to be understood as being modified in all instances by the term "about". Accordingly, unless otherwise indicated, the numerical parameters set forth in the specification and claims are approximations that may vary depending upon the desired properties to be obtained.

The present inventors have solved the problems of the prior art by providing a method for producing esters comprising reacting methyl biodiesel or free fatty acids with a polyhydroxylated alcohol in the presence of a biocatalyst, wherein the biocatalyst is a fermented solid produced by culturing microorganisms in agricultural waste by solid state fermentation.

In a first aspect, the invention includes producing a low cost lipase for use in the synthesis of biolubricant esters. For this purpose, agricultural waste is used as culture medium in solid state fermentation processes.

Solid state fermentation makes it possible to use low cost raw materials as culture media for microorganisms, with a single fermentation medium. In this method, the substrate not only provides nutrients for culturing the microorganisms, but also serves as a carrier for cell growth.

In the context of the present invention, the term "agricultural waste or waste materials" is understood to mean the solid residue (cake) of the oily raw material. Preferably, solid residues from palm oil and cottonseed oil extraction are used.

The term "inoculum" is understood as the cells of the microorganism in the form of spores or plant cells which are used to initiate the fermentation process. Preferably, the microorganism is a filamentous fungus. More preferably, the fungus is of the genus rhizomucor. Even more preferably, the fungus is a Rhizomucor miehei (Rhizomucor miehei) species.

The term "fermenter" is understood as a chamber with controlled temperature and humidity for growing microorganisms on the cake.

The term "fermented solids" is understood as dry fermented cake at the end of the solid state fermentation process, which contains biomass of microorganisms and lipases.

In one embodiment, water is added to the solid state fermentation based palm oil cake or cotton seed oil cake in a ratio that is ideal for the fermentation process, and then mixed into the inoculum.

The wetted and inoculated cake is then incubated in a fermenter during which the microorganism grows and, as a result of its metabolism, produces a group of lipases with high synthesis capacity.

At the end of the solid state fermentation, the fermented cake is subjected to a drying step and then used for catalytic reactions. Preferably, drying is carried out by lyophilization or forced air.

A low cost enzymatic biocatalyst produced by a solid state fermentation process is used in a transesterification or hydroesterification reaction to produce a biolubricant ester.

In the transesterification process, methyl biodiesel is reacted with a polyhydroxylated alcohol to produce a biolubricant ester. Preferably, the methyl biodiesel is soy methyl biodiesel or castor oil methyl biodiesel. Preferably, the polyhydroxylated alcohol is neopentyl glycol, trimethylolpropane or pentaerythritol.

In one embodiment, the transesterification reaction is conducted with a biodiesel to alcohol molar ratio of 2 to 5 and optionally 1 to 3% (w/w) water. The fermented solids were used as biocatalyst at a concentration of 10-30% (w/w). The reaction is carried out in a reactor at a temperature of 30-50 ℃ and under stirring at atmospheric pressure.

In a preferred embodiment, the reactor used is a stirred tank at atmospheric pressure with controlled temperature in which the transesterification reaction is carried out.

Under these conditions, the methyl ester undergoes transesterification with an alcohol to produce a biolubricant ester and methanol as a by-product. The product is isolated at the end of the process.

The hydroesterification process consists of a first hydrolysis reaction and a second esterification reaction.

In one embodiment, the first reaction (hydrolysis) comprises mixing the oil containing oil and the buffer in a volume ratio of 1:1, followed by addition of the lipase in a proportion of 1-2% w/v of the weight of the oil.

The reaction is carried out in a reactor at a temperature of 30-40 ℃ and atmospheric pressure with stirring. In these conditions, the oil is hydrolysed and free fatty acids and glycerol are produced as by-products. The free fatty acids are separated from the buffer, glycerol and lipase prior to use in the esterification reaction.

In a preferred embodiment, the oil-containing oil is soybean oil or castor oil and the lipase is a commercial lipase from Candida rugosa (Candida rugosa) or a lipase obtained from dormant castor oil plant seeds.

In a preferred embodiment, the reactor used is a temperature-controlled stirred tank at atmospheric pressure, in which the hydrolysis reaction is carried out.

In one embodiment, the second reaction (esterification) is carried out by reacting the free fatty acid and the polyhydroxylated polyol with water in a free fatty acid to alcohol molar ratio of 2 to 5 and optionally 1 to 3% (w/w). The fermented solids were used as biocatalyst at a concentration of 10-30% (w/w). The reaction is carried out in a reactor at a temperature of 30-50 ℃ and atmospheric pressure with stirring.

In a preferred embodiment, the reactor used is a stirred tank at atmospheric pressure with controlled temperature in which the esterification reaction is carried out.

In these conditions, the free fatty acid is esterified with a polyol to produce a biolubricant ester and water as a by-product.

The biolubricant esters obtained by the process of the present invention were analysed with respect to their physicochemical properties, which showed satisfactory physicochemical characteristics consistent with those of currently available biolubricants.

The viscosity of the biolubricant is the most important property of these fluids, as it is directly related to the formation of a film that will protect the metal surface against erosion.

The viscosity index is a parameter of the oil viscosity behavior at temperature. The higher the value, the less the change in oil viscosity with temperature. In general, the value of the viscosity index is determined by a calculation that takes into account the viscosity of the product at 40 ℃ and 100 ℃.

The flow point measures the lowest temperature at which the oil still flows and is the test used to evaluate the behavior of a lubricating oil when subjected to low temperatures.

The physical and chemical properties of the biolubricants such as viscosity, viscosity index and flow point are higher than those of mineral-based lubricants.

The properties and performance of the biological lubricant of the present invention can be further improved by using additives that are compatible with the lubricant and preferably that are non-toxic and biodegradable.

The esters produced by the process of the invention are particularly useful in lubricating applications where the maximum operating temperature is below 120 ℃, but where the ambient temperature remains above-40 ℃.

The biological lubricant of the present invention can be used as engine oil, pressure transmission liquid, rolling liquid, and the like.

The invention will be further illustrated by the following examples which are not to be considered as limiting. As will be apparent to those skilled in the art, the present invention is not limited to these specific embodiments.

Examples