GB2543487A

GB2543487A - Plant growth enhancing composition and method for producing it

Info

Publication number: GB2543487A
Application number: GB1518160.5A
Authority: GB
Inventors: Griggs Russell; Martin Hugh
Original assignee: Gci Corp Ltd
Current assignee: Gci Corp Ltd
Priority date: 2015-10-14
Filing date: 2015-10-14
Publication date: 2017-04-26
Also published as: EP3362421A1; GB201518160D0; WO2017064297A1

Abstract

A composition produced from a combination of spent coffee grounds, coffee chaff, and sawdust has a carbon:nitrogen balance of from about 25:1 to about 40:1 and is useful for enhancing plant growth. The mixture has a moisture content of from about 58wt% to about 63wt%. The composition additionally may comprise yeast, e.g. Yarowla lipolytica. Also claimed is a method of producing a plant growth enhancing composition comprising providing coffee grounds, coffee chaff and sawdust, hydrating the mixture, mixing to a substantially homogenous blend and maintaining a substantially aerobic environment within the mixture by intermittent or continuous tumbling to promote decomposition.

Description

PLANT GROWTH ENHANCING COMPOSITION AND METHOD FOR

PRODUCING IT

FIELD OF THE INVENTION

This invention relates to a plant growth enhancing composition produced from: a combination of spent coffee grounds, coffee chaff* and sawdust. The invention also relates to an improved method of producing the plant growth enhancing composition utilising a yeast to promote the rate of decomposition.

BACKGROUND OF THE INVENTION

The use of spent coffee grounds in the production of compost or other plant growth enhancing compositions or fertilisers is known. Such spent coffee grounds are routinely produced as a waste product from the manufacture of instant coffee granules. As such, there have been a number of approaches to utilising this waste product, so as to generate an additional income stream, to reduce the overall amounts of waste to be disposed of, and to reduce adverse environmental impact.

Similarly, cpffp fhaff, hulls, or husks have been utilised in the producuon of compost or other plant growth enhancing compositions pr fertilisers.

For example, GB 1372466 discloses a method of processing spent coffee grounds in order to reduce the moisture content thereof. The processed dried spent coffee grounds are reported to have numerous applications, for example, as fertilisers, soil conditioners, fuel, a constituent of animal feeding stuffs, spacings in abrasives, or as a source of oil. However, the document provides no detail as to how the processed dried spent coffee grounds may be converted into useful fertilisers or soil conditioners, nor whether their use actually improves nutrient levels in the soil or enhances plant growth.

Spent coffee grounds are also used in combination with various: minerals and/or inorganic chemicals to produce soil conditioners and fertilisers. For example, spent coffee grounds are used as a component of a urea-formaldehyde granular fertiliser in

Ul 4,210,830, the other components of which include urea, urea-formaldehyde concentrate, water, potassium chloride, monoammonium phosphate, and sulphuric acid. However, such granular slowfrelease fertilisers represent only a very small fraction pf the worldwide fertiliser mafpt, and as such the demand for such products is relatively low. Similarly, US 3,640,696 describes a soil conditioner comprising spent coffee grounds and silicon dioxide, and GB 1292049 describes a soil conditioner produced from the waste products of instant coffee production and silica, silicate, or aluminium oxide.

Dried coffee refuse is also used as an additional component in composts produced: from organic matter. For example, US 6,224,771 describes a compost produced from household waste and manure together with a medium comprising dried coffee refuse, wheat bran or coconut fibre, and a ferment bacillus. This additional medium is used to |Cce|erate fermentation of the compft.

However, the majority of the above documents utilise either spent coffee grounds or coffee chaff, rather than a mixture of both of these waste products. Moreover, the documents generally include the coffee waste products as only minor components of the mixture used tg produce the compost or fertiliser, with other mineral or organic substances being used as the major components. Furthermore, none of the above documents discloses a composition that utilises both spent coffee grounds and coffee chaff as the main constituents, and also shows increased growth rates of plants grown using the composition.

Accordingly, there is a need for an alternative composition that acts effectively as a plant growth enhancer, and is produced using the waste products of instant coffee production, including both spent coffee grounds and coffee chaff.

SUMMARY OF THE INVENTION

The present invention is directed to providing a plant growth enhancing composition produced using spent coffee grounds and coffee chaff as the main components.

In accordance with a first embodiment, the present invention provides a plant growth enhancing composition produced from a combination comprising spent coffee grounds, coffee ehaf| and sawdust, wherein the combination has a carbon:nitrogen balance of from about 25:1 to about 40:1.

Preferably, the combination has a carbonmitrogen balance of from about 31:1 to about 40:1, mom preferably about 35:1.

Such a combination of fresh spent coffee grounds, coffee chaff, and sawdust has surprisingly been found to produce a particularly high quality growth mediuifl The appropriate degree of microbiological activity is attained by measuring the carbon and nitrogen levels of the separate components, which then permits the calculation of a suitable blend to reach a carbon: nitrogen balance of from about 25:1 to about 40:1 by adjusting the proportions of the starting materials.

The determination of carbon / nitrogen levels is preferably carried out using a commercially available analyser, for example a vafio MACRO cube of Eiementar, Hanau, Germany, This is a commercially available macro analyzer designed tor tie fast and iffe determination of M/pfotein in plant material, food and feed as ah environmentally friendly alternative to the classical Kjeldahl method. The apparatus can also be applied for the determination of CN levels, e.g. in agricultural research.

In accordance with a second embodiment, the present invention provides a method for producing a plant growth enhancing composition comprising: providing spent coffee grounds, coffee chaff, and sawdust, in suitable amounts to achieve a carbon:nitrogen balance of from about 25:1 to about 40:1, hydrating the mixture to a moisture content of from about 55wt% to about 65wt%, mixing to a substantially

Homogeneous blend, and maintaining a substantially aerobic environment within the mixture by intermittent or continuous tumbling to promote the decomposition process.

Preferably the mixture has a moistu re content of from about 58wt% to about 63wt%, more preferably about 60wt%.

It has surprisingly been found that the addition of a yeast to the mixture used to produce the plant gpwt| enhancing: composition promotes the rate of decomposition. Preferably, the yeast used in the method of the invention is Yarowla llpolytica. Preferably, the yeast is added to the misiure ih an amount of from about 0.75g/!itre of mixture to about 1 Jg/litre of mixture, more preferably in an amount of about l.Og/iitre to about 1.4 g/litre of mixture, most preferably in an amount of about 1.2?g/litre of mixture.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows the results of the chemical analysis results of the sawdust/SCG 40:1 mixture during the decomposition process as described in Example 1.

Figure 2a shows the fresh wt./plant WRAP test results for tie compositions as described in Example 1,

Figure 2b shows the dry wt./piant WRAP test results for the compositions as described in Example 1,

Figure 2c shows the ieaves^piant WRAP test results for the compositions as described in Exampie 1,

Figure 2d shows photographic images of the plants grown in the WRAP testing for the compositions as described in Example I.

Figure 3 Shows the results of the chemical analysis results of the sawdust/chaff/SCG 30:1 mixture as described in Example 2.

Figure 4a shows the fresh Wti/plant WRAP test results for the compositions as described in Example 2,

Figure 4b shows the dry whlplant WRAP test results for the compositions as described in Example 2.

Figure 4c shows the leayes/plarit WRAP test results for the compositions as described in Example 2,

Figure 4d shows photographic images of the plants grown iri the WRAP testing for the compositions as described in Example 2,

Figure 5a shows the effect of spent coffee grounds (SCG) and fresh yeast (FY) gn dry weight yield of radish as tested using: the procedure described in Exampie 3,

Figure 5b shows the effect of spent coiee g·rounds (SCG) and fresh yeast (FY) on radish leaf dry weight as tested using the procedure described in Example 3.

Figure 5e shows the effect of spent coffee grounds (SCG) and fresh yeast (FY) on radish rdpt dry weight as tested using the procedure described in Example 3.

Figure 5d shows the effect of spent coffee grounds (SCG) and fresh past (FY) on radish total biomass as tested using the procedure described in Example 3,

Figure 5e shows the effect of spent coffee grounds (SCG) and fresh yeast (FY) on total area of radish root as tested using the procedure described in Example 3,

Figure 5f shows the effect of spent coffee grounds (SCG) and fresh yeast (FY) on fraction of colour in radish as tested using the procedure described in Example 3i

Figure 6 shows the temperature differentia! achieved using Yarowia iipoiytica Compared to a control uin§ the procedure described in Example 4.

DETAILED DESCRIPTION OF THE INVENTION

The following definitions shall apply throughout the specification and the appended claims.

Within the context of the present specification/ the term "comprises" is taken to mean "includes" or "contains" i.e. ether integers or features may be present, whereas the term "consists of" is taken to mean "consists exclusively of'.

Within the present specification, the term "about" means plus or minus 20%; more preferably plus or minus 10%, even more preferably plus or minus 5%; most preferably plus or minus 2%.

Within the present specification^ the term "spent coffee grounds" refers to ground roasted coffee beans which have been used either in the manufacture of instant coffee or in restaurants, cafes, or other food and drink outlets in the preparation of fresh coffee beverages.

Within the present specification/ the term "coffee chaff" refers to the hulls or husks of the coffee beans.

Within the present specification, the term "sawdust" refers to fine particles of wood; including wood shavings, wood chips, and both coarse and fine sawdust.

It has surprisingly been found that combining sawdust with spent coffee grounds and coffee chaff and subjecting the mixture to a composting or decomposition process results in a high quality and particularly effective plant growth enhancing composition. By contrast/ the use of other substrates, such as straw andllr paper resulted in unusable mixtures. The use of sawdust is particularly desirable in view that it is also generated p | waste product Trim manufacturing processes and is available in bulk quantities at low cost.

It has been found that a carbon: nitrogen balance for the mixture of spent coffee gfllrids, coffee chaff, and sawdust has surprisingly good results at from about 21:1 to about 40:1. Outside this range, it has been found that temperatures generated are too high or low, or ammonia is produced leading to a foul smill

Accordingly, the present invention provides a plant growth: enhancing composition produced from a combination comprising spent coffee grounds, coffee chaff, and sawdust, wherein the combination has a carbon:nitrogen balance of from about 25:1 to about 40:1.

The present invention also provides a method for producing a plant growth enhancing composition comprising: providing spent coffee grounds, coffee chaff, and sawdust, in suitable amounts to achieve a carbon:nitrogen balance of from about 25:1 to about 40:1, hydrating the mixture to a moisture content of from about 55wt% to about 65wt%, mixing to a substantially homogeneous blend, and maintaining a substantially aerobic environment within the mixture by intermittent or continuous tumbling to promote the decomposition process,

The quality of the plant growth enhancing composition may be optimised by controlling the conditions under which it is produced.

It is important to adjust the moisture content of the mixture of components to a level of from about 55wt% to about 65wt%. Higher or lower levels of moisture have been found to provide insufficient biological activity and a higher risk of oxygen depletion. Most preferably, the moisture content Is adjusted to about 60wt%.

It is also important that the individual components used to produce the plant growth enhancing composition are mixed together to form a substantially homogeneous blend. Preferably, such mixing is achieved by using a tumbler. This can be achieved lh: a domestic composter or industrially available high output continuous machinery used for large scale processing of organic waste.

The decomposition prfee§s is promoted by maintaining a substantially aerobic environment within the mixture. This is typically achieved by tumbling of the mixture, and such tumbling can be either intermittent or continuous. In one preferred embodiment of the invention, the tumDlshg is eorlihuous. In another embodiment of the invention, the tumbling is intermittent. For example, tumbling can be performed once daiiy or once weekly.

Preferably, the tumbling is carried out using commercially available: machinery, eg a Bighanna composter. The preferred machinery is a model primarily used for food waste composting and was part of a WRAP test process Ibr Her Majesty's Prison Service and is widely used. This model has the capacity required (preferably about 115- about 340 kg/day; about 800 - about 2400 kg / week; about 41 - about 124 tons / annum; and is suitable for about 275 - about 650 households). It has a length of about 6408 mm, width of about 2000 mm, height of about 2195mm and a cylinder having a volume of about 8m3 however there are smaller alternative units within the Bighanna range providing similar service.

In one particularly preferred embodiment of the invention, a yeast is added to the mixture in order to promote the rate of decomposition. This allows for faster production of the plant growth enhancing composition which is important when working in a commercial scale.

Accordingly; the present invention also provides a method for producing a plant growth enhancing composition comprising: providing spent coffee grounds (scg), coffee chaff, and sawdust, in suitable amounts to achieve a carbon:nitrogen balance of from about 25:1 to about 40:1, hydrating the mixture to a moisture content of from about 55wt% to about 65wt%, adding a yeast in an amount of from about i,75g/iitre Of mixture to about 1.5g/htre of mixture; mixing to a substantially homogeneous blend, and maintaining a substantially aerobic environment Within the mixture by intermittent or continuous tumbling to promote the decomposition process.

Preferably, the yeast used in the method of the invention is Yarosvia iipolytica. Yarowia iipolypa is an unusual past species in that it is a non-pathogenic aerobic (oxygen-requiring) species, which ||s an; ability to utilise "non-conventiona!" carbon sources for its growth> including hydrophobic substances such as fail acids, fats and oils, organic acids, and alcohol. The yeast is also able to secrete lipase and bio-surfactants, Its metabolic activity is particularly evident within the temperature range of from about 3Q°e to about 40°C.

Alternatively, one or more yeasts can he used. The yeast las the ability to metabolised the lipid content of SCG (which is about 19% w/w), thereby raising the ottai level of metabolic activity, therefore heat output, during composting

Preferably, t|e yeast | added to the mixture in an amount of about l,25g/litre of mixture, EXAMPLES Example 1

Batches of sawdust/SCG 40:1 compost and chaff/sawdust/SCG 30:1 compost were prepared.

Preparative steps were consistent throughout the Examples, Moisture content of each component of the mix, together with their C:N values were measured by the RAU laboratories. Spreadsheet calculations enabled simultaneous calculation of proportions needed to reach the mixture specification on moisture content of 60% (water being added as required and in variable quantities depending on amount in the mixture components) and C:N ratio. Moisture content of each biend; was checked immediately after mixing, Sufficient batches were made to fill the containers (either $8® or 80 llpl).

Compost m#ces> prepared as above, were made in batches measured by volume, in weight calibrated containers for the particulate materials. Sufficient multiple batches were mixed to fill the containers in which the composting process took place (either 80 or 180 litres).

Yeast was added by mixing in after the compost had been prepared.

The contents were thoroughly mixed by hand every 7 to 10 days, by emptying, mixing Thoroughly, and resfil|p|.

An analysis of the chemical constituents of the composition was carried out at two separate time-points after 83 cays and 175 clays during the decomposition process, and the results are shown in Figure 1.

The compositions produced; were used in a study of plants growth rates using standard WRAP testing procedures. The: testing procedure is published by REAL (Renewable

Energy Assurance Limited) as Method code: OFW004-006, Version 3.0, Published: August 2015.

In this regard, the standard WRAP procedure is a method for assessing tomato plant performance and assessing contamination by weed seeds and other propaguies in compost samples. Its basis is Annex D in the British Standards Institution's Publicly Available Specification for Composted Materials^ 2005 edition (PAS 100:2005). The Annex D methodology was designed as a single multipurpose test assessing weed content, tomato seed germination, seedling growth and abnormalities in a sphagnum peat medium containing 20 to 33 % by volume of the compost sample under evaluation.

This method of test investigates how a compost-amended peat growing medium (the Test Sample) affects tomato seed germination, top-growth and health, when compared with a standard peat growing medium (the control) under controlled conditions over a 28 day test period, the eiect of variable soluble sait contents in the composts under test (as judged by their electrical conductivity) isssubstahtially limited by controlled dilution of the compost with sphagnum peat that has low conductivity. This means that any significant negative response in the Test Sample that Is not seen in the control can be taken to indicate phytotoxic factors in the compost, which might then feiuirefurther testing before the compost can be used.

This method includes simultaneous assessment of weed seeds and Other propaguies that may be present in the Test Sample, taking account of any that appear in the control.

This test is designed to assess many of the compost grades used in growing media and most soil improvers, such as those with particle size ranges 0 - 6 mm, 0 - 10 mm, 0 -12 mm, 0 -15 mm, 0 - 20 mm, 0 - 25 mm, and 0 - 40 mm. However, is not suitable for composts that retain no soil-like particles, such as mulch grades that consist only of coarse woody particles, e,g. 10 - 40 mm, PAb 100 does not require such muicn grades to undergo this test for tomato plant performance and weed seeds.

The results of the plant growth rate WRAP tests are shown in Figures la to 2d, It is evident that loth compositions palled thf WRAP standard test, with the chaff/sawdust/SCG mixture producing a higher biological response to the reference growth medium (a peat based growth medium).

Example!

Batches of the chaff/sawdust/SCG 30:1 compost were prepared. The procedure was as detailed in Example 1,

An analysis of the chemical consituents of the composition was carried out on completion of the decomposition process, and the results are shown in Figure 3.

The compositions produced were used in as study of plant growth rates using standard WRAP testing procedures as discussed above.

The results of the plant growth rate WRAP tests are shown in Figures 4a to 4d. Again the chaff/sawdust/SCG 30:1 composition passed the WRAP standard test, and confirmed earlier testing. The plant growth rates shops visually in Figure 4d when using the Example composition in comparison with the reference growth medium (a peat based growth medium) are particularly striking.

Example 3 A trial was carried out to assess the action of the fresh yeast (FY), in this case, the species Yarowia lipolytica, with and without the addition of spent coffee grounds (SCG) on plant growth rates.

The trial utilised radish as the test organism, in a randomised block design with fresh yeast added to a range of SCG concentrations in soil.

The following treatments were incorporated ini) the growing medium: 1. SCG1% p/w) 2. SCG 2% 3. FY 1% 4. FY 2% 5. SCG+FY 1% 6. SCG+FY 2% 7. Control (no treatment)

The results of this trial are shown in Figures 5a to 5f. It was evident that SCG alone promoted growth and quality characteristics of the radii giants grown in the test procedure: While Yarowia lipolytica, when applied alone, had no effect on growth compared to control values, SCG in combination with Yarowia iipoipca produced a significantly higher biomass production (mainiy leaf tissue) with some enhancement of cosmetic appearance. The results support the hypothesis that the yeast may promote the conversion of the SCG into a mom eieetive plant growth enhancing composition.

Example 4

Following on from the promising results achieved in Example 3 above, Yarowia lipolytica was incorporated into a chaff/sawdust/SCG mixture (30:1 C:N ratio) at a rate of approximately l,25g yeast/iitre compost mixture.

The temperature of the mixture was monitored over a decomposition period of 95 days and compared with a control chaff/sawdust/SCG mixture (30:1 C:N ratio) lacking the additional yeast com ponent.

It was observed that the larowia Iipolytica-treated container maintained a near consistently elevated temperature differentia! above the untreated bin. The temperature differential graph is shown in Figure 6.

Over the course of the 95-day trial, the Yarowfa lipofytica-treated container had accumulated at least 140 day-degrees of heat over the untreated container, aiding in promotion of the decomposition process.

Embodiments have been described herein in a concise way, It should be appreciated that features of these embodiments may be variously separated or combined within the invention.

Claims

CLAIMS 1, : A plant growth enhancing composition comprising a m||ure of spent coffee grounds,: coffee chaff, and sawdust; wherein the combination has a carbor:nitrogen balance of from? about 11:1 to about 40:1,
2, A composition according to claim 1 wherein the mixture has a moisture content of from about 58wt% to about S3wt%.
3, A composition according to ciaim 1 or claim 2 wherein the composition additionally comprises a yeast:
4, A composition according to claim 3 wherein the yeast is Yarowia iipplytica.
5, A composition according to ciaim 3 or claim 4 wherein the mixture comprises yeast in an amount of from about 0.75g/iitre of mixture to about 1.5g/iitre of mixture, 6: A composition according to claim 5, wherein the mixture comprises yeast in an amount of from about l.Og/litre to about 1,4 g/litre of mixture A composition according to claim 5 or claim 6, wherein tie mixture comprises yeast id an amount of about l,25g/litre of mixture. 8> A method for producing a plant growth enhancing composition comprising;: providing coffee grounds, coffee chaff, and sawdust, in suitable amounts to achieve a cafbon:nitro|en balance of from about 25:1 to about 40:1, hydrating the mixture to a moisture content of from about 55wt% to about 65wt%, mixing to a substantially homogeneous blend, and maintaining a substantially aerobic environment within the mixture by intermittent or continuous tumbling Ιο; promote decomposition. 9s A plant growth enhancing composition or a method substantially ass herein described.