Enzymatic processing plant and method of enzymatic processing

Abstract

An enzymatic processing plant for continuous flow-based enzymatic processing of organic molecules. The enzymatic processing plant including an enzymatic processing area, wherein the enzymatic processing area includes a turbulence-generating pipe with a repeatedly changing centre-line and/or a repeatedly changing cross-section, for generating turbulence to mix a reaction mixture and prevent sedimentation of particles as the reaction mixture is flowing through the turbulence-generating pipe. The enzymatic processing plant and the enzymatic processing area are arranged such that the reaction mixture is subjected to turbulence within the enzymatic processing area for a reaction time of 15 minutes or more.

Claims

1. An enzymatic processing plant for continuous flow-based enzymatic processing of organic molecules, comprising: an enzymatic processing area, wherein the enzymatic processing area comprises a turbulence-generating pipe with a repeatedly changing centre-line and/or a repeatedly changing cross-section, for generating turbulence to mix a reaction mixture and prevent sedimentation of particles as the reaction mixture is flowing through the turbulence-generating pipe, wherein the turbulence-generating pipe is provided in a stacked, coiled or nested arrangement, in one or more broadly horizontal layers, wherein the enzymatic processing plant and the enzymatic processing area are arranged such that the reaction mixture is subjected to turbulence within the enzymatic processing area for a reaction time of 15 minutes or more, wherein turbulence is generated in the turbulence generating pipe without moving parts, and is generated throughout the bulk of the flow, wherein the turbulence-generating pipe comprises a number of notional repeating units, wherein the number of repeating units is greater than 10, wherein the plant is arranged to operate with the reaction mixture having a flow velocity of less than 2 m/s through the turbulence generating pipe, wherein the enzymatic processing area includes one or more turbulence generating pipe(s) with a total length of at least 50 m, and wherein the turbulence-generating pipe has an average diameter in the range of 20 mm to 200 mm.

2. A plant as claimed in claim 1, wherein the reaction time is more than 30 minutes.

3. A plant as claimed in claim 1, wherein the turbulence-generating pipe has a changing cross-sectional area.

4. A plant as claimed in claim 1, wherein the turbulence-generating pipe is a corrugated pipe.

5. A plant as claimed in claim 1, wherein the flow of the reaction mixture within the turbulence-generating pipe is turbulent at Reynolds numbers of less than 1000.

6. A plant as claimed in claim 1, wherein the turbulence generating pipe includes a layer of immobilised enzymes attached to the inner surface of the pipe.

7. A plant as claimed in claim 1, comprising an injection point for introducing reagents which change the characteristics of the reaction mixture, wherein the reagent is an acid, a base or water.

8. A plant as claimed in claim 1, comprising a heat exchanger for heating at least a portion of the turbulence-generating pipe.

9. A plant as claimed in claim 1, comprising a separator system comprising a three-phase decanter operable to output a flow of oil and oil-soluble components, a flow of water-soluble components, and a flow of sediment, and/or a centrifuges and/or a filter.

10. A plant as claimed in claim 1, wherein the plant is a modular system.

11. A ship fitted with the plant of claim 1.

12. A plant as claimed in claim 1, wherein the reaction time is less than 90 minutes.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Certain preferred embodiments will now be described in greater detail by way of example only with reference to the drawings, in which:

(2) FIG. 1A shows a part of a corrugated turbulence-generating pipe;

(3) FIG. 1B shows a part of a helical turbulence-generating pipe;

(4) FIG. 1C shows a part of a turbulence-generating pipe having bends;

(5) FIG. 1D shows a part of a turbulence-generating pipe having a changing cross-sectional shape;

(6) FIG. 1E is a cross-sectional view of a pipe with a helical corrugation pattern;

(7) FIG. 2 shows the parameters of depth and width for a corrugated pipe; and

(8) FIG. 3 shows a modular plant for enzymatic processing.

DETAILED DESCRIPTION OF THE INVENTION

(9) FIG. 1A shows a part of a corrugated turbulence-generating pipe. The pipe has a diameter of about 60 mm, corrugation depth e of about 6 mm, and p/e of about 13. In such a pipe, turbulence occurs at Reynolds number above approximately 800.

(10) FIG. 1B shows a part of a helical turbulence-generating pipe. The pipe has a diameter of about 60 mm. The pitch of the helical centre-line is 20 mm, and the radius of curvature of the helical center-line is 1.5 mm.

(11) FIG. 1C shows a part of a turbulence-generating pipe having bends. The pipe has a cross-section that is square with sides of about 60 mm. The bends are at an angle in the range of 15° to 30°

(12) FIG. 1D shows a part of a turbulence-generating pipe having a changing cross-sectional shape. The pipe changes from a circular cross-section to an elliptical cross-section. The cross-sectional area is about 2800 mm.sup.2.

(13) FIG. 1E is a cross-sectional view of a pipe with a helical corrugation pattern, the helix having a single start.

(14) FIG. 2 shows the pitch (width) p and depth e of corrugations on a corrugated pipe.

(15) FIG. 3 shows a modular plant for enzymatic processing of organic molecules. In this case, the plant is for hydrolysis of protein in a protein-lipid mixture. The use of the plant for hydrolysis is exemplary and not limiting on the invention; it will be apparent that a similar apparatus could be used for any multi-stage enzymatic process. Further, in this case, the raw material processed by the system is fish. However, the use of the plant for processing fish is exemplary and not limiting on the invention; it will be apparent that a similar apparatus could be used with a different raw material. Further examples of processes making use of the proposed device are set out below.

(16) The particular enzyme (and hence reaction conditions) used in each stage will depend on the raw material and the products to be obtained, and can be chosen accordingly.

(17) The plant comprises a mixing chamber for pre-mixing the reaction mixture prior to injection into the first hydrolysis stage. Aside from an input for receiving the raw materials and an output for connection to the next section of the hydrolysis plant, the mixing chamber is sealed and has a negligible headspace, so as to reduce the amount of oxygen which is brought into contact with the reaction mixture. This reduces oxidation of oils present in the feedstock. The mixing chamber is heated by a heat exchanger in order to bring the reaction mixture to a temperature suitable for optimal enzymatic action in the first hydrolysis stage.

(18) The fish, water, and a protease are mixed and heated in the mixing chamber. After mixing, the reaction mixture is pumped by a pump into the first hydrolysis stage. Here, protein in the reaction mixture is hydrolysed to form high-molecular weight peptides. The first hydrolysis stage is a corrugated pipe having a mean diameter of 46 mm, with a plurality of 180° bends, with radius of curvature of 200 mm.

(19) In the first hydrolysis stage, the reaction mixture has the following properties:

(20) Density ρ=1000 kg/m.sup.3

(21) Viscosity μ=0.02 Ns

(22) Reynolds number Re=800

(23) Mean velocity ν=0.35 m/s

(24) The volume flow rate for a given diameter is given by:

(25) $\begin{array}{cc}\stackrel{.}{V}=\frac{\pi }{4}\star D^2\star v& \mathrm{Equation}3\end{array}$
For the parameter values given above, this gives a volume flow rate of 2.1 m.sup.3/h. The total length of the first hydrolysis stage is of the order of 1 km, and the processing time is of the order of 1 hour.

(26) Towards the end of the first hydrolysis stage, the corrugated pipe is heated to a temperature hot enough to deactivate (denature) the protease.

(27) The flow from the first hydrolysis stage is pumped using a pump to a separator system. The separator system comprises a three-phase decanter operable to output a flow of oil (lipids, and oil-soluble components), a flow of water-soluble components, and solid components.

(28) The solid components from the separator system (primarily bone) are treated in two separate ways. A portion of the solids is passed to a drier (for example by a conveyor, not shown) and is dried to form fishmeal. The fishmeal is output as a product of the system (useful outputs of the system are shown as shaded arrows). A second portion of the solids is passed (for example by a conveyor, not shown) to a further enzymatic treatment stage for further treatment.

(29) The further enzymatic treatment stage includes an input means for modifying the pH or ionic properties of the reaction mixture to suit the optimal operating conditions of the enzyme (shown as a hatched arrow). The product of the further enzymatic processing is output as a product of the system, after drying in a further drier (not shown).

(30) The oil-soluble components from the separator system are also treated in two separate ways. A portion of the oil-soluble components is passed to a polisher (using a pump, not shown) which cleans the oil. The cleaned oil is separated into component parts using a centrifuge and filter (not shown) and the resultant components are output as products of the system. A second portion of the oil-soluble components is passed to a lipid hydrolysis stage (using a pump, not shown) and is treated with lipases. The lipid hydrolysis stage includes an input means (shown as a hatched arrow) for modifying the pH or ionic properties of the reaction mixture to suit the optimal operating conditions of the lipase. In addition, the input means allows for the introduction of water. This is necessary since lipases are water soluble (not oil-soluble). Thus, for the lipase to act on the lipids, a suspension may be formed, allowing contact between the lipase and lipids. Provision of a turbulence generation pipe which mixes efficiently but minimizes the formation of emulsions is useful in such a process. The product of the lipase processing is output as a product of the system.

(31) The water-soluble components from the separator system are also treated in two separate ways. A portion of the high-molecular weight peptide components are filtered out (using a filter, not shown) and are output from the system as a product. The remaining portion is input into a second hydrolysis stage.

(32) The second hydrolysis stage includes an input means (shown as a hatched arrow) for modifying the pH or ionic properties of the reaction mixture to suit the optimal operating conditions of the second protease. The protease hydrolyses high-molecular weight peptide components to form medium-molecular weight peptide components. Towards the end of the second hydrolysis stage, the second hydrolysis stage is heated to a temperature hot enough to deactivate the protease.

(33) From the second hydrolysis stage, a portion of the medium-molecular weight peptide components are filtered out using a filter and are output from the system as a product. The remaining portion is input into a third hydrolysis stage.

(34) The third hydrolysis stage includes an input means for modifying the pH or ionic properties of the reaction mixture to suit the optimal operating conditions of the third protease (shown as a hatched arrow). The protease hydrolyses medium molecular weight peptide components to form low-molecular weight peptide components.

(35) Towards the end of the third hydrolysis stage, the third hydrolysis stage may, if needed, be heated to a temperature hot enough to deactivate (denature) the protease.

(36) From the third hydrolysis stage, the reaction mixture is passed to a separator system, which separates low-molecular weight peptide components from any remaining solids or oil soluble components. Any solid components are passed back to the drier (or the enzymatic bone treatment stage) and any oil components are passed back to the lipid hydrolysis stage (or the polisher). The low-molecular weight peptide components are output from the system.

(37) The skilled person will appreciate that not all of these components are essential, and depending on the raw materials and desired end products, a combination of the elements of this system will be employed.

(38) The processing plant may be used for other processes as well, and it provides advantages for any process requiring relatively long reaction times. Various possible processes are set out in the examples below:

Example Hydrolysis Process 1

(39) The process uses whole sardines (anchovy) with Alcalase (Novozymes), ground through 6 mm dyes, a raw material/water ratio 50/50 (w/w), and a reaction temperature 60° C. Targeted % DH=17 (% DH=number of peptide bonds cleaved/total number of peptide bonds), estimated reaction time 45 minutes based on info from the enzyme manufacturer. The enzyme added is 0.1% (d.w) of raw material (w.w) excluding added water. The plant is operated with a capacity 7 MT per hour, of which 3.5 MT of fish and 3.5 MT of water. The tube length will be 863 m.

(40) Supplementary information: In this case no large bone particles are present, and thus the risk of clogging due to sedimentation of hard particles is low. The whole length of the tube is of similar shape and diameter throughout, although viscosity decreases down the line. A boost pump is fitted in ⅓ the length from the inlet as a safety guard towards clogging. The concentration of peptides increases with time as protein hydrolysis goes on. Peptides can act as emulgators, and a key point is to avoid the formation of emulsions along the tube.
Reaction Mixture Properties:

(41) Density ρ=1000 kg/m.sup.3

(42) Viscosity μ=25 cP (inlet

(43) Selected Properties of the Flow:

(44) Reynolds number Re=1125

(45) Mean velocity ν=0.32 m/s

(46) Using these parameters gives the diameter D=88 mm.

(47) For the parameter values given above, this example has a volume flow rate of 7 m.sup.3/h.

Example Hydrolysis Process 2

(48) This example uses heads and backbones from salmon to be hydrolysed using Protamex (Novozymes). The enzyme concentration is 0.1% (d.w) of raw material (w.w). The raw material undergoes grinding through 6 mm dyes, and is mixed in a ratio of raw material/water 50/50 (w/w), before being processed at a reaction temperature of 50° C. The targeted degree of hydrolysis % DH=10 (% DH=number of peptide bonds cleaved/total number of peptide bonds), and the estimated reaction time 30 minutes based on information from the enzyme manufacturer.
Supplementary information: In this case where large bone particles are present the optimal configuration of the hydrolysis unit is a first part (⅓) where there is less risk of sedimentation of the bone particles resulting in a clogged tube—due to relative high viscosity. As process runs then the viscosity declines increasing the risk of clogging. Therefore, in this embodiment the hydrolysis unit is constructed by means of three different tube diameters linked together.
The hydrolysis unit parameters are given below for the pipe inlet, at the mid-length and at the pipe outlet.
Reaction Mixture Properties:

(49) Density ρ=1000 kg/m.sup.3

(50) Viscosity μ=23 cP, 17 cP and 9 cP

(51) Selected Properties of the Flow:

(52) Reynolds number Re=1035, 1655, 3620

(53) Mean velocity ν=0.23 m/s, 0.32 m/s and 0.43 m/s

(54) Using these parameters gives diameters of D=104 mm start, 88 mm in mid-section and 76 mm the last part. The total tube length is 586, distributed into 137 m first part, 192 m mid part and 257 m last part. There will be a boost pump before section 2 and before section 3.
The volume flow rate for this example would be 7 m.sup.3/h.

Example Hydrolysis Process 3

(55) In this case hydrolysate processed from salmon frames and heads by means of Alcalase (Novozymes) is further processed through a secondary hydrolysis using Flavourzyme (Novozymes) which is an exopeptidase/endopeptidase complex specially designed to optimize taste and reduce bitterness. The hydrolysate was diluted to contain 10% dry matter, of which protein is the major part (approx. 90%). The substrate contains virtually no lipids. The reaction time is 20 minutes and the reaction temperature 55° C. The enzyme concentration is 0.1% (d.w) of raw material (w.w).
Supplementary information: In this case the substrate is a free-flowing liquid with no particles nor lipids are present, and thus there is no risk of clogging or formation of emulsions. Viscosity is low throughout the process tube, which is of similar construction throughout.
The following exemplary calculation uses values for the parameters which may be typical of a working system:
Reaction Mixture Properties:

(56) Density ρ=1040 kg/m.sup.3

(57) Viscosity μ=6.5 cP

(58) Selected Properties of the Flow:

(59) Reynolds number Re=1811

(60) Mean velocity ν=0.09 m/s

(61) Using these parameters gives the pipe diameter D=125 mm. The tube length is 109 m.

(62) For the parameter values given above, the volume flow rate is 4 m.sup.3/h.

(63) It should be apparent that the foregoing relates only to the preferred embodiments of the present application and the resultant patent. Numerous changes and modification may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the invention as defined by the following claims and, the equivalents thereof.