CA1275956C - Substrate for growing shiitake mushrooms - Google Patents

Abstract

SUBSTRATE FOR GROWING SHHTAKE MUSHROOMS
ABSTRACT OF THE DISCLOSURE
A non-sterile, pasteurized nutrient substrate composition is disclosed suitable fro growing shiitake mushrooms. Its composition and preparation are described. In addition, the use of the substrate composition is taught fro the commerical, large-scale growth of shiitake mushrooms in trays or beds.

Description

~27s~6 ~U13STRAT~ FOR GR()WING 5HIITAK~3 MUSHlROOMS
TE ClHNICAL FIELD
The present invention is directed to ~ method of making a composted substrate on which shiit~ke mushrooms, c~n be grown.
The invelltion is further dir~cted to a methocl o~ growing shiitake mushroom3 which h ~uitable for commercial production.
BACKGROUND OF THE INVENTION
~ orest mushrooms, or shiitake (Lentinu~ edodes), have been used both as food and medicine in Asia for hundred~ of years.
However, cultivation of shiitake h~s remalned in a primiti~,re state until ~rery re~ently. Shiitake traditionally have been grown on tree trunks, some types of trees supporting more abun~nt growth than otherq. Growth of shiit~ke on trees typi~Qlly reguire~ between on~
and two years until the first crop of fruiting bodie~ is produced. ~
One method which has been ~ound to expedite the growth of shiitake involves growing the mu~hrooms aseptically in plflstie bags or in trsys on ~terilized ~ub~trAte. Such substrate~ generally include ~aYv du~t, ~gasse, ~t~w~ paper chlps and the like, whi~h are supplementedl with nutrients ~uch ~ ~tarch, yeast, sugars ~nd protein. Il~ing this method, mushrooms ~an be harvested in as little a~ three to four mont~ a~ter ino~ldation.
Un~ortunately9 thi~ aseptic ~rowth method is ill 3uited to the establi~hed equipment and procedures employed by l~rge sc~le, com-merci~l growers of white mushrooms (~). White mu3hrooms ~re grown on a pasteur1zed, composted substrate In tr~ys.
There~ore, there is a need ~or a method o~ growlng ~hlltnke mush-rooms which is ~ompatlble lNlth the technlques snd flppAr~tus used by the indu~try.

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The b~sic pro~edure for commerci&lly growing mushrooms involves either bulk pasteurlzation o~ compo~t in highly inQulated rooms ~alled "tunnels,n or pa~teuri~tion o~ compost fn tray3. Such compost i~ then impregn~ted with rnushroom mycelia. This step is referred to as ~pQWning~ arld is generally E~erformed in individuql beds or tra~s to fRc11itQte h~ndling and to m~imize space utilizs-tion. Altern~tively, the sp~wning ¢arl be performed in bulk,. The spawn-impregnated compost is then allowed to develop under con-trolled temperature and moi~ture conditions. When the compost is sp~wned in bulk, the trays are ~illed after the sp~wn h~s perme-~ted the compost. Orlce the hyphae of the mushrooms have per~
meated the compost9 condltions are ~ltered to csuse the mushrooms to fruit. In the e~3e o~ white mushrooms, a thin layer o~ soil, sand or pe~t i~ placed on top of the bed. The process o~
covering the bed is referred to AS "casingn. In the case of ~hitake, fruiting is stim~ted by significantly reducing the temper~-~e of the mushroom beds. After the first crop of fruit l~s been harvested~ ~dditional cy¢leg of ~ruiting occur, referred to ~s "bre~ks'~ or "n~lshe37', until the nutrients in the compost have been depleted.

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It is an object of an aspect of the invention to provide a substrate for growing shiitake mushrooms.
It is an ob~ject of an aspect of the inven-tion to provide a substrate for growing shiitake mushrooms which is compatible with the apparatus and techniques used by commercial mushroom growers.
It is an object of an aspect of the invention to provide a substrate for growing shiitake mushrooms which allows a first harvest within two to four months of spawning.
It is an object of an aspect of the invention to provide a method for growing mushrooms which eliminates the need for aseptic growth conditions.

SUMMARY OF THE INVENTION
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759~i6 -2b-A non-sterile, p~steurized, nutri0nt ~ub~trate ~omposi-tion 3uit~ble for growing shiitake mushrooms consisting essenti~lly of a mixture of a vegetative w~ste ~nd a mirer~l fertilizer, which ~omposition h~s been sequentially composted first at ambient and then at mesothermic temperature~.
A process i~or pr~p~ring a nutrient substrate composi-tion suitable for growth of shiihke mushrooms comprising prep~ring a ~ompost mixture cos~isting essentislly of a veget~tive wa~te, a misleraI rertilizer and ~ater, said mixture haviog ~ moisture content of AboUt 65 to 80%;
~erobically digesting the mixture at ~mbient tempera-tures for between sbout 1 and 9 days;
p~steurizing the mixture; and further digesting the mi~ture st a mesothern~ic tem-per~ture oi between about 45 to 55C for between about 3 to S
da~s.

A method for growing shiit~ke mushrooms on the non-sterile, pasteurized, nutrient substrate o~ ~laim I comprising mixing shiitake spawn with said nutrient sub~tr~te;
maintaining said spa~qn ~nd substrate mixture ~der conditions which cause shiit~ke myeelia to permeate the spawn and substrate mixt~e; and causing the shiitake to ~ruit by maintaining the shiitake mycell~ under a suitable temperature ~nd light regime.
A non-sterile, p~steurized, nutrient ~ubstrate ~mposi-tion suitable for growlng shiit~ke mushrooms cc~ngisting essentially o~ on ~ d~y weight basi~ a mixture o~ ~7-50% wheat straw, 24-47% corn cobs, 8-20% cotten3eed meal, 2-6~6 gypsum, 0-3%
potash and O.S-3% Am monium ~trate~

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DETArLED DESCRIPTION
A compost formul~tion h&~ been ~ound which supports the growth of ~hiitake mushrooms and i3 prepared osing techniques Rkin to those commercially used to prep&re compost ror growing white mushrooms. The eompost COllSiSt~ es~enffRlly of ~erobially degraded fnrm or ~orest (vegetative) wa~te materiaI~, supplemented with min-eral fertilizers. It is important that the Qddition oi~ animal wasge materisls, such as poultry manure and cow m nure, be avoided.
Although not completely understood, it is believed th~t heavy metals, such 8S zin~ and msnganese) or organi~ amides present in such Qnimal waste materials inhibit shiitake development. Composts prepQred using the combination Or vegetatîve waste material, animal w&ste material end miner~l sources have pre~riously been used as a substrate for growing other genera of mæhrooms.
The vegetative waste material used to prepare the compost generally consistg of cellulosic and ligni~containing material3. Such materi~ls include cottonseed meal, pe~nut meal, rape seed meal, corn ~ nd ~ereal grain straws such as wheat, o~t and rice, snd the like. In a preferred embodimerlt of the invention, the compost ~rmldstion contairls A mixture of Yegetative wastes com-prising corn cob, cereal straw and cotltonseed meal.
The mineral ~ertilizer component typically contains sources of calcium, nitrogen ~nd potassium. The term fertilizer, used herein, refers to a cheml~l mixture which~ ia combination ~ith the vege-tative waste, i3 capable Or ~u~taining mushroom growth. Any ~ources of c~lcium, nitrogen snd potassium known in the art m~y be used, either organic or inorganic, with the exclusion of manures.
A preferred compo~ition o~ the minersl fertilizer component includes ~ mixture of gypsum, ~mmonium nitrate ~nd potAsh.

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A broad r~nge OI component ratios c~n be wed when pr~
paring ~ compost for growing shiit~ke. The ~egetative w~ste com-ponent comprises the bulk of the compost mixture. ~ a prererred formul~tion9 whe~t straw is a m~or component, comprising ~rom about 37-50% of the compost mixture on ~ dry weight ~sls; eorn cobs can comprise frorn about 24~796 by weight; cottonseed me~l ~an comprise from about 8-20% by ~e3ght. Miner31 fertili3ers will typically comprise from ~bout 3% to about 12% by weight of the compost mixture. For e~Qmple, in ~ preferred rorm~ation gypsum is added to the eompost mixture ~t between about 2 and 6% by weight; potash is ~dded at about ~3% by weight; ~nd annmonium nitrate i3 added at ~bout 0.5-3% by weight.
Other suitable vegetative waste m~terhls and miner~l ferti-lizers mny be identified asld substituted Yor those noted ~bove on the basis o~ routine testing. Unle~s otherwise indicflted, all per-centages reported throllghout the speciîication ~nd claims are by weight.
The vegetati~e waste materi~l alld the mineral fertilizers are blend~d together to form a compost mixture which is chopped, wetted ~nd assembled into p~les for aerobic digestion. The mixture of the veget~tive wastes ~nd minernl ~ertilizers i3 wetted to a moisture content o~ between about 6~ ~nd 80%. Prefer~bly, the moisture- content is between 72 and 76% o~ the compogt mixture~
The compost mixture is the-l aerob}c~lly digested by endogenou3 mlcroorganism~, th~t is microorganisms such as ~sc$eri~, typically ~ and fw~gi ~hich are n~turally on the ~e~e-tative msteri~l. The mixture cRn be Iormed into piles which flre mech~nicfllly mixed periodically (about every two to three dRys~ to insure suitable conditions for aerobic di~estion OI the vegetntive wa~tes. Such nerobJc dlgestion (composting) contlnue~ ~or between ~bout one and nine d~ys. When ~erobic digestlon OI the eompost mixture is c~rried out for longer than ~bout one weelc, the result-lng yield OI mu3hrooms grown on that compost is reduced.
Thereîore, It Is preferred to allow aerobic digestlon for between AboUt 4 and 7 d~ys.

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After digestion, the compost mixture 3s p~steurized ~t a temperat~e of Qbout 60C to about 6SC for between about four to six hours. It i3 important, how~ver, thQt the mixture not be steri-lized. Pa~teurization c~n be nocomplished economic~lly by use of live ste~m in an insul~ted space such as a compost tunnel. Thi~
step is ~im~d at eliminating organism3 in the compo3t which would compete with the growing rnushrooms ~or nutri2nts.
The compost mixture can then be p~lrti~lly cocled to anintermediate temperature, between the pasteuri~ation temperature and ambient tempePature. This temperature ~ondition, hereln termed mesothermio9 is generally between about ~5 ~nd 55C, preferably between ~bout 4g~ and 54 ~C. Keeping the compo~t ~t such mesothermic conditions for between 2bout three to five days allows for iurther degradation o~ the compost by endogenous, thermophilic org~nisms into usable nutrientc. If the compost is previougly sterili~ed such rurther degr~d~tion ~qould not be possible in a reason~ble time.
The cornpo~t cRn then be further cooled to ambient tempera-ture, generally between QboUt 18~ ~d 30C. Pre~erably, the tem-perature will be ~bout 23 to a7c. A~ these ambient temperA
tures, shiitake mushroom spawn can b~ mixed into th~ compost ~; without l~rm. ~rain spawn conaisting of myeelia and their growth substrute of rge, wheat~ bQrley or: the like, is pre~erred as u form - Or mushroom sp~wn. The spawn is ~dded to t~e compost ~t a~out B to 15% by dr~ weigS~t.
- Ths tr~y~ can be i~illed be~ore or arter mixing of the sp~wn `~ with the compost. Ii~ desired~ the spswn can be Allowsd to grow in bulk until the compost become~ thoroughly myceluim-impregnated be~ore the tr~y3 are filled. The spawn and compost can be pres3ed into tray~, ~nd covered wlth a moi~ture barrier, ~uch ~s plastic Pilm or ~hee~; or gl~s~ plllte. The moi~ture ~rri~r is gen-erally ramo~/ed when ~ruiting begins, and the beds kept molst by ~pplIcstion oP A Illi~t 0~ water.

- 6 - ~L27~i~51Ei Using the described methodologies, a ~ ;t h~rYe~t of shJitake mu~hrooms c~n be obt~ined within ~bout two to ow~ month~. Sub-sequent breaks can be har~rested every tell to fourteen d~ys9 approximately. Such a cycle will prev~il ror about eight to ten months, until the nutrient value o~ the ~ubstral:e ~s been depleted.
Applicant has found that the combination o~ the compost formulation and the sequenti~l composffng procedure described ~boYe is ideally sl1ited for producing ~ cosnpost ~uit~ble ror growing shiit~ke mu3hrooms. Quite unexpectedly, shiit~ke call be grown in high yield on the compost, whi~h is not steriliæed.
No light is required during $he sp~wn-run~ However, under cropping condiffon3, light is introduced. As recognized in the prior Art~ nouresc~nt tubes delivering between ~bout 300 and 659 lux are sufficient~ As i9 also well known in the art, rruiting of the mush-rooms can be stimul~ted by ~ubject~ng the mycelia to a "~old shoek9' tPeatm0nt. Under croppirlg conditions the air temperature is preferably lowe~ed to promote ~ruiting, to ~bout la to 20C while the compost temper~turs i~ about 16 to ~5C.
An important feature o~ the present invention is th~t the direct addition OI high gr~de or refined food sour~es such QS
starch, yeast, sugar and protein to the sub~trate is not required.
Instead, th0 present invention reliæ upon the in ~itu production o~
such ingredients by endogenous microorganisms in the presen~e of the vegetative w~ste and mineral i~ertilizer m3~ture. Une2~peetedly, the prs~ence in the compost of endogenous thermophiles which survi~e the pa~teurization treatment, provide ~urther digestion of the sub~trate, and remain in the compo~t during spawning, do not adversely inhibit shiitake ~velopment and growth.
The compost o~ the present invention and the method ~or its preparal:ion are pArtlcularly well ~ulted to growing ~hiitake mush-rooms com mercially or on a large ~c~lle. Su~h oompost c~n be prepared and handled erficiently wing ~guipment alrendy us~d industrlally ror grol~ving ~ or white mushrooms.

~L~7~5i6 The ~ollowing working exRmple~ are not intended to limit the scope of the Invent~on, but merely to exempliîy concretely the methods to be employed and result3 which c~n be expected when the present invention i5 used.

The following components were Qdded together in the listed proportions9 mixed and thoroughly wetted to about 75% moisture content to prepare the compo~t o~ the present invention.
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Wheat ~trsw 38.1 Corn cobs 46. 6 Cot ton~eed m~al 8. S
~r~non i um n i t r a t e 1 . 4 Pota~h 1. 4 Gypsum 4. 0 To f~cilitate ~erobic digestion, the pile wa~ turned ~nd ricked 2-3 times during the period Or 7 to 9 d~ys prior to pa~teuriz~tion. LiYe steam was used to r~ise the ~ir temperature to 60-65C for ~6 hours and thereby pQSteUrize the compost. The air temperst~e w~s ~lowly reduced to between 49 and 54C for 3 to 5 day~ to permit further dlgestlon of the compost by endogenou~ thermophile~ The compo~t w~ thel~ cooled ~urther to 24C o~er 2 to 3 day~, ~t ~rhich time it was ready for spawning.

rlous ~ 3t~in~ o~ shiitake mu~hroom3~ ~ll oi~ which Qre ava~l~blQ rrom the Department of Pl~nt Pethology, Pennsylvania State ~iYe~ity, were ~osYn on the ¢ompost prepared flccording to E~ample L.
I~ushrooms were h~rvested o~rer ~ period of 8 months a~t~r ~pawning and weighed. Conver~ion e~iciencie~ are expressed as Wet wel~t of mushroom~
oa The ti me required to a~hieve fir~t harvest from spa~vning wa~ also determined. The re~t~ Are ~ummarized below.

~hl it~ke Days to Yield ~ rsl ~tr~in _t ~X~rve~t ~m2) E~ _ cy ~) ~C-379 111 7. 7 45 WC-325 107 3. 1 18 ~ 31~ lg~ 0.2 wc-3ns 160 0. 9 While the present invention h~s been described with respect to preferred embodiment~9 it should be und~rstood thflt Y~lriOUS
chflnges m~y be m~de without de~arting ~rorn the ~pirit ~nd scope o~ the invention 619 pQrltic~arly cl~imed below.

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Claims (18)

1. A non-sterile, pasteurized, nutrient substrate composi-tion suitable for growing shiitake mushrooms consisting essentially of a mixture of a vegetative waste and a mineral fertilizer, which composition has been sequentially composted first at ambient and then at mesothermic temperatures.

2. The composition of claim 1 wherein the vegetative waste consists essentially of cellulosic and ligning-containing mate-rials and the mineral fertilizer consists of sources of potassium, calcium and nitrogen.

3. The composition of claim 2 wherein the mineral fer-tizilizer is selected from the group consisting of potash, gypsum, ammonium nitrate and mixtures thereof.

4. The composition of claim 2 wherein the cellulosic and lignin-containing materials are selected from the group consisting of cereal straw, cottonseed meal, corn cobs and mixtures thereof.

5. A process for preparing a nutrient substrate composi-tion suitable for growth of shiitake mushrooms comprising preparing a compost mixture consisting essentially of a vegetative waste, a mineral fertilizer and water, said mixture having a moisture content of about 65 to 80%;
aerobically digesting the mixture at ambient tempera-tures for between about 1 and 9 days;
pasteurizing the mixture; and further digesting the mixture at a mesothermic tem-perature of between about 45 to 55°C for between about 3 to 5 days.

6. The process of claim 5 wherein the pasteurization is performed at a temperature of about 60 to 65°C for a period of about four to six hours.

7. The process of claim 5 wherein the mixture is aerobically digested at ambient temperature for about four to seven days.

8. A method for growing shiitake mushrooms on the non-sterile, pasteurized, nutrient substrate of claim 1 comprising:
mixing shiitake spawn with said nutrient substrate;
maintaining said spawn and substrate mixture under conditions which cause shiitake mycelia to permeate the spawn and substrate mixture; and causing the shiitake to fruit by maintaining the shiitake mycelia under a suitable temperature and light regime.

9. The method of claim 8 wherein the shiitake spawn is allowed to grow and permeate the nutrient substrate in bulk.

10. The method of claim 8 wherein a tray is filled with the nutrient substrate and spawn mixture immediately after mixing and the filled tray is covered with a moisture barrier.

11. The method of claim 8 wherein the spawn is mixed with the compost in a tray and the filled tray is covered with a moisture barrier.

12. The method of claim 8 wherein a light regime of about 300 to 650 lux is maintained during mushroom fruiting.

13. The method of claim 8 wherein successive flushes of mushrooms are harvested until the nutrient value of the substrate is depleted.

14. The method of claim 8 wherein the nutrient substrate is the composition of claim 2.

15. The method of claim 8 wherein the nutrient substrate is the composition of claim 3.

16.The method of claim 8 wherein the nutrient substrate is the composition of claim 4.

17. A non-sterile, pasteurized, nutrient substrate composi-tion suitable for growing shiitake mushrooms consisting essentially of on a day weight basis a mixture of 37-5096 wheat straw, 24-47% corn cobs, 8-20% cottenseed meal, 2-6% gypsum, 0-3%
potash and 0.5-3% ammonium nitrate.

18. The method of claim 8 wherein the nutrient substrate is the composition of claim 17.