WO2001039591A2 - Airlift bioreactor for harvesting sprouts - Google Patents

Abstract

A method and apparatus for harvesting large quantities of sprouts according to either a batch process or a continuous process. A bioreactor (10) includes a chamber (12) containing seeds/sprouts and a growing medium, such as water. The growing medium is sparged with a lifting fluid that prevents anaerobiosis, promotes germination of said seeds into sprouts, and prevents matting of the sprouts or seed hulls. The bioreactor (10) includes features for maintaining the sterility of the chamber (12) and for preventing contamination of the sprouts.

Description

AIRLIFT BIOREACTOR FOR HARVESTING SPROUTS

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is generally directed to an airlift bioreactor for producing sprouts either in batches or continuously. In particular, the present invention is directed to harvesting large quantities of broccoli sprouts, which the have been discovered to be high in glucosinolates.

2. Description of the Related Art

The sprouting industry currently utilizes a variety of devices to grow sprouts from the seeds of plants. These devices consist typically of rotary drums or trays that can be disinfected by washing with various sterilants (e.g., sodium or calcium hypochlorite) or of containers for holding molded plastic shelf-packs in which the sprouts are grown directly. A water supply is provided and light is provided in some cases. Growth is typically for a period of 3 to 7 days. Seeds used in the process are typically not pre-treated, or are surface disinfected for a period of 15 minutes or so with a variety of sterilants, or are surface disinfected and then soaked for a period of one to several hours. This process is, however, fraught with opportunity for microbial contamination - overgrowth of the sprouts with plant pathogens or with human pathogens is difficult to predict and/or to control. Even if seeds are initially de-contaminated, the system does not remain sterile in a traditional sprouting operation.

United States Patent 2,677,217 to Pentler et al. discloses a method of growing edible seed sprouts including completely submerging seeds in water, and continuously aerating the water during sprout growth.

British Patent 2 037 134 to Grimmett discloses an open-topped vessel that contains water and seeds to be germinated. Air is introduced at the bottom of Grimmett's vessel for agitating the suspension of seeds in the water.

However, the devices of both Pentler et al. and Grimmett are susceptible to contamination either by seed or water borne bacteria or fungi.

United States Patent 4,057,930 to Barham discloses a method and apparatus for hydroponically sprouting seeds including aerating the water during sprout growth (e.g. , see Figure 5). However, in contrast to the present invention, Barham also teaches a mat for supporting the seeds above the water.

SUMMARY OF THE INVENTION

The present invention is designed to treat the developing sprouts as if they were a single strain, microbial fermentation. The present invention provides an apparatus and method of growing sprouts wherein the entire operation (from surface disinfecting to soaking seeds to growing the resultant sprouts) is approached much like a microbial incubation/fermentation, with preservation of sterility at all steps.

According to the present invention, a steam- or chemical- sterilizable chamber provides for the introduction of sterile water and air through appropriate locks. Seeds are introduced to a pre-sterilized chamber, which is sealed and then flooded with a sterilant (e.g., 2% calcium hypochlorite in water) and a surfactant. According to a preferred embodiment of the present invention, gentle agitation may be provided via an impeller turning inside the chamber. According to a most preferred embodiment of the present invention, the chamber inlet for the ingress of the growing medium into the chamber is configured to facilitate agitating the contents of the chamber. This is a major improvement over conventional practices that typically entail merely leaving the seeds to sit in a 5-gallon pail of sterilant. The lack of any agitation in these conventional practices results in uneven exhausting of the sterilizing potential. Following a period of about 15 minutes, sterilant is drained from the chamber and replaced by sterile air through a filter-lock in the chamber. The chamber is then thoroughly rinsed free of sterilant, with the seeds in situ, by introducing and voiding multiple changes of sterile water or another liquid. Following the last rinse, the seeds are allowed to remain in the sterile water at an appropriate temperature (e:g. , 68 °Q) and are sparged with oxygen or a mixture of gases in order to prevent anaerobiosis and promote seed germination. Temperature control is maintained with one or more heat exchangers. According to a preferred embodiment, the heat exchangers are mounted on or in the chamber, or the wall of the chamber.

Alternatively, water is drained and reintroduced on a periodic basis to maintain the seeds / sprouts in a fully hydrated state and sufficient air / oxygen are introduced to allow the catabolic processes of metabolism associated with germination to proceed unhindered. Light is provided at the end of the growth period via a submersible lighting device while adjustment is made, if needed, for the introduction of CO. required by photosynthesis.

Another embodiment of the invention is to grow seeds/sprouts in a sterilizable "fermenter" such as those typically used for microbial fermentation. We have discovered that sprouts can be grown completely immersed in a liquid state provided they are sparged with air. Alternatively, sparging can be performed with 100% O2 or with a CO2/O2 or other gas mixture or the system can be operated hyperbarically. For example, broccoli spnouts grown in a stirred water-containing vessel with constant aeration were harvested, spun in a salad-spinner and had similar organoleptic properties and glucoraphanin levels as traditionally grown sprouts.

Alternatively, light is not provided in the sprouting chamber, thus simplifying its design, but high intensity light is provided during the harvest, washing and packing process such that the sprouts will become green and thus more attractive to consumers. Alternatively, or coincidentally, germicidal ultraviolet light is provided throughout the growth period in order to inhibit the proliferation of any bacteria or fungi that escape the surface sterilization procedure (seeds harboring internal infection might be expected to escape this process). This ultraviolet light, likely by virtue of its effect as an abiotic inducer of plant defense reactions, was discovered to have the additional unanticipated benefit of raising the levels of glucosinolates, specifically or glucoraphanin, in the resulting sprouts.

Alternatively, or coincidentally, antibiotics (preferred embodiments being natural antibiotics such as sulforaphane, sinigrin, allyl isothiocyanate, etc.), are introduced into the water of hydration such that any bacteria that escapes the sterilization process, will be inhibited or killed and thus will not achieve high numbers in the short time of incubation of the seeds/sprouts.

Additionally, flavor enhancing compounds, preservatives or plant nutrients or growth regulators can be introduced into the sprouting chamber in order to enhance product characteristics. Another preferred embodiment of this invention includes the use of seeds which have been previously treated (e.g. , with γ-irradiation) to reduce surface-associated contaminants or seeds which have been sorted by mechanical means (e.g., computer- vision, sonic transduction, flotation) in order to reduce the incidence of damaged and potentially contaminated seeds.

Another preferred embodiment of this invention includes the use of feed water or gas that has been treated in such a way as to exert a static or inhibitory effect on any potential contaminants (e.g., ozonation or chlorination or water; pretreatment of chamber/ seeds with peroxide vapor).

Another preferred embodiment of this invention is the introduction of fiberoptic or Green Fluorescent Protein bioprobes, specifically designed to detect the presence of common foodborne contaminants such as Salmonella, Shigella, E. coli and Listeria. These extremely sensitive probes (patent applied for) permit in-line, real-time, continuous process monitoring which would allow for run abortion prior to packaging / shipping, thus potentially halting food contamination prior to packaging or shipping and performing a tremendous public health service.

Advantages of growing sprouts using the apparatus and method according to the present invention include a bioreactor that has few or no moving parts, and which is compact in size with a minimal cost to purchase and operate. Additionally, the bioreactor chamber is easy to clean, is readily sterilized or sanitized (e.g., chemically, with steam, or with dry heat), and promotes sterile growth of sprouts. Further, the bioreactor chamber may be used for initial seed treatment, e.g., with hypochlorite, and washing. The advantages of the present invention further include the ability to treat growing sprouts with nutrients and anti-microbacterials, and the ability to adjust the temperature and pH, e.g., with citric acid, of the growing medium. Also, the present invention advantageously separates seed hulls from sprouts, and yields relatively dry sprouts for packaging, without the need for conventional centrifuging techniques. The above objects and advantages, as well as other objects and advantages that will become clear from the following description of the present invention, are realized by a method of growing sprouts. The method comprises adding seeds to a chamber; flooding the chamber with a combination of a sterilant and a surfactant; rinsing the seeds in the chamber with at least one charge of sterile water to remove the combination of the sterilant and the surfactant; adding a fresh charge of the sterile water to the chamber; continuously recharging the chamber with sterile water for hydrating the seeds; sparging the chamber with a lifting fluid for preventing anaerobiosis and for promoting germination of the seeds into sprouts; and harvesting the sprouts. The above objects and advantages, as well as other objects and advantages that will become clear from the following description of the present invention, are also realized by an apparatus for germinating seeds in a growing medium and for harvesting sprouts germinated from the seeds. The apparatus comprises a chamber adapted for receiving the seeds; a chamber inlet adapted for ingress of the growing medium into the chamber; a chamber outlet adapted for egress of the growing medium and sprouts out of the chamber, the chamber outlet having interchangeable separating fixtures, the interchangeable separating fixtures including: a first fixture adapted for passing the growing medium out of the chamber and adapted for retaining the sprouts in the chamber, and a second fixture adapted for passing the growing medium out of the chamber and adapted for passing the sprouts out of the chamber; and a sparger adapted for dispensing a lifting fluid into the growing medium.

The objects and advantages of the present invention will be set forth in the description that follows, and in part will be readily apparent to those skilled in the art from the description and drawings, or may be learned by practice of the invention. These objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows an apparatus according to a preferred embodiment of the present invention for producing a batch of sprouts.

Figure 2 is a cross-section taken along line II-II in Figure 1 showing a chamber inlet configuration according to the present invention.

Figure 3 shows an alternative chamber inlet configuration according to the present invention. Figure 4 is a cross-section taken along line IV-IV in Figure 1 showing a sparger configuration according to the present invention.

Figure 5 shows an alternative sparger configuration according to the present invention.

Figure 6 illustrates a first condition of a preferred method according to the present invention for producing a batch of sprouts.

Figure 7 illustrates a second condition of a preferred method according to the present invention for producing a batch of sprouts. Figure 8 illustrates a third condition of a preferred method according to the present invention for producing a batch of sprouts.

Figure 9 shows an apparatus according to a preferred embodiment of the present invention for continuously producing sprouts. Figure 10 is a schematic illustration of a variable opening floor sieve.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An apparatus and method for producing batches of sprouts according to the present invention will now be described with respect to Figures 1-8.

As shown in Figure 1, for example, a bioreactor 10 according to the present invention comprises a vertical chamber 12 having a sealed bottom 14. An openable or removable lid 16 provides a closed system. The chamber 12 is preferably constructed from transparent or translucent plastic or glass. The construction material should be food grade and suitable for steam, heat or chemical sterilization. Preferably, the chamber 12 is a right-circular cylinder having a height to diameter ratio (H/d) greater than 3. According to a most preferred embodiment of the present invention, the chamber 12 is constructed such that H/d > 4.

A chamber inlet 18 provides ingress for the growing medium into the chamber 12. The chamber inlet 18 is located proximate to the bottom 14 of the chamber 12. The chamber inlet 18 may be oriented with respect to the chamber 12 to provide radial (Figure 2) or tangential (Figure 3) flow for agitating the contents of the chamber 12.

According to a preferred embodiment of the present invention, the growing medium is potable, filtered, and preferably deionized, water, i.e., sterile water. The growing medium may flow through the chamber 12 in a single pass or be recirculated with a pump 20 and cleaned 22, e.g., by filtration or UV exposure. Nutrients or anti-microbials may also be added 24, and the pH may be adjusted, e.g. , with citric acid. A heat exchanger 26 may also be used to temperature treat the growing medium. Of course, the present invention may employ other treatments and additives for preparing the growing medium to enter the chamber 12. Moreover, different combinations of treatments or additives may be employed according to the present invention. According to a preferred embodiment of the present invention, the growing medium is sparged by a combination of bottom and top spargers. The bottom sparger 28 dispenses a lifting fluid, e.g., air or an air/water mixture, proximate to the bottom 14 of the chamber 12. According to a most preferred embodiment of the present invention, the bottom sparger 28 has an annular configuration (Figure 4) or spiral configuration (Figure 5). The lifting fluid may be supplied to the bottom sparger 28 via a first feed 30 extending from the top opening (Figures 1 and 4) or through the sidewall of the chamber 12 (Figure 5). Of course, different configurations of the bottom sparger 28, e.g. , multiple concentric annulus, may be used according to the present invention.

The top sparger 32, or plunging jet sparger, is preferably a straight, vertically oriented pipe that also dispenses a lifting fluid, e.g., air or an air/water mixture, proximate to the opening of the chamber 12. The top sparger 32, which may dispense the same or a different lifting fluid than the bottom sparger 28, maintains circulation of the chamber contents near the opening for avoiding matting of the seed hulls or sprouts. The lifting fluid is preferably supplied to the top sparger 32 via a second feed 34 extending through the chamber opening; however, the lifting fluid could also be supplied through the sidewall of the chamber 12. When the lid 16 is used to seal the chamber 12, a vent 36 removes the lifting fluid that is exhausted from the growing medium. The exhausted lifting fluid may be expelled from the apparatus or refreshed and cleaned 38, as necessary, before being recycled.

A submersible lighting device 39 may be used at the end of the growth period while adjustment is made 38, if needed, for the introduction of the CO2 required for photosynthesis.

A chamber outlet 40 provides egress from the chamber 12 for the growing medium 40a, the seed hulls 40b, and the sprouts 40c. The chamber outlet 40 is located in the sidewall of the chamber 12 at the fluid level of the growing medium, i.e., proximate to the top of the chamber 12. The chamber outlet 40 includes different fixtures each having a different size sieve. One fixture 44a (Figure 6) has a sieve size for passing only the growing medium only (~ 1 mm sieve openings; depends on seed size). Another fixture 44b (Figure 7) has a sieve size for passing only seed hulls with the growing medium (3-4 mm sieve openings), and yet another fixture 44c (Figure 8) has a sieve size for passing the sprouts with the growing medium (20-30 mm sieve openings). The small size sieve openings are used during the early stages of the process to withdraw the growing medium from the chamber 12 (Figure 6); the medium size sieve openings are used during an intermediate stage to draw off the seed hulls (Figure 7); and the large size sieve openings are used during the harvesting stage to collect the sprouts (Figure 8). According to a preferred embodiment of the present invention, broccoli, alfalfa, onion, mustard, cress, etc. sprouts are suitable for harvesting in the chamber. In general, bean sprouts are not preferable for harvesting in the chamber according to the present invention. Seeds of the conifer species have been found to be preferable inasmuch as they yield sprouts that are high in glucosinolates.

According to a preferred embodiment of the present invention, the initial seed concentration is no more than 20-25 g/L to avoid sprout aggregation, the chamber height (H) is no more than 8 ft ( - 240 cm) to facilitate installation in conventional building structures; and the height to diameter ratio is at least 3:1 (most preferably, approximately 4: 1).

In operation, one bag of seeds, nominally 50 lbs. (22.73 Kg), and an initial seed density of 20 g/L, requires a chamber volume of 1,135 liters. However, a 240 cm tall chamber having the required volume would have a H/D ratio of 3.09. Thus, it has been found that by using one-half of one bag of seeds (25 lbs or 11.36 Kg), a 240 cm tall chamber may be constructed according to the following parameters:

Initial seed Chamber Diameter

H/D ratio density (g/L) volume (L) cm inches

15 757 63.4 25.0 3.78

20 568 54.9 21.6 4.37

25 454 49.1 19.3 4.89

Example of a first preferred embodiment according to the present invention:

The chamber 12 is constructed as a vertically oriented Lucite (Plexiglas^®) cylinder that is 24" tall and has a 6" diameter. Thus, the height to diameter ratio (H/D) is 4. The bottom 14 of the chamber 12 is sealed with a Lucite plate. A 0.25" diameter chamber inlet 18 extends through the sidewall of the chamber 12 proximate to the bottom 14 of the chamber 12. A 3" diameter chamber outlet 40 extends through the sidewall of the chamber 12 approximately 24" above the bottom 14 of the chamber 12. A fine mesh nylon sieve passes only the growing medium through the outlet, and a stainless steel sieve having 0.3125" holes passes seed hulls with negligible sprout loss. During harvesting, the outlet is unobstructed. The bottom sparger 28 is configured as a 5" diameter annulus made from 0.25" diameter tubular stainless steel. The bottom sparger 28 is inserted from the opening to the chamber 12 and rests on the bottom 14 of the chamber 12. The diameter of each hole in the bottom sparger 28 is < 0.015625" (- 0.4 mm). A 0.25" feed 30 extends from the opening to the chamber 12 for supplying the lifting fluid to the bottom sparger 28. The top sparger 32 is configured as a 0.25" diameter stainless steel tube extending 8" below the growing medium fluid level 42. The top sparger extends downward from the chamber opening in a radially centered position within the chamber 12. The diameter of each hole in the top sparger 32 is also < 0.015625" ( — 0.4 mm); however, there are fewer holes than the bottom sparger 28.

The temperature of the growing medium, 15 liters of deionized water, was tested at 25 °C and at 28-29°C, with 300-400 g of seeds during a 2-3 day growing period. The flow rate of the growing medium was 600 ml/min, and the flow rate of the sparging fluid was ml/min and ml/min, respectively, for the bottom and top spargers. The fine mesh nylon sieve was installed across the chamber outlet 40 for the first 30 hours. Thereafter, the stainless steel sieve was installed across the chamber outlet 40 until the sprouts were harvested. This resulted in a de-hulled sprout yield of 3 to 1 for a two day growth period.

Example of a second preferred embodiment according to the present invention: A chamber 12 having a height (H) of 4 feet ( - 120 cm) tall and a diameter

(d) of 12 inches (- 30.4 cm) has a volume of 84.8 L with the H/D = 4. For an initial seed density of 20 g/L, 1696 g ( - 3.74 lbs) of seed would be placed in the chamber 12. As compared to the first example which was described for use with one-half of one bag of seeds, this second example has approximately 15% of the volume, is 50% as tall, and has a diameter that is approximately 55 % as great. Preferably, this second example would likely use a bottom sparger 28 having a plurality of concentric annuluses or a multiple turn spiral configuration.

Example of a preferred sequence of steps according to the present invention:

1. (optional) pre-treat a chamber with peroxide vapor to inhibit contamination 2. steam or chemically sterilize the chamber including inlets/outlets for a growing medium and for a sparging fluid 3. (optional) treat seeds with γ-radiation to reduce incidence of contaminated 4. (optional) mechanically sort the seeds to reduce incidence of damaged seeds

5. (optional) pre-treat the seeds with peroxide vapor to inhibit contamination

6. add the seeds to the chamber

7. seal the chamber 8. flood the chamber with a sterilant and a surfactant

9. agitate the contents of die chamber for approximately 15 minutes to promote uniform exhausting of the sterilizing potential

10. drain the sterilant and replace with sterile air

11. (optional) ozonate/chlorinate sterile water to inhibit contamination 12. rinse chamber/seeds with multiple changes of the sterile water to remove the sterilant 13. add a fresh charge of the sterile water

14. control temperature of the sterile water via heat exchangers on/in the chamber 15. (optional) drain/reintroduce the sterile water to maintain the seeds in a fully hydrated state, and introduce air/oxygen to facilitate catabolic processes of metabolism during germination 16. (optional) expose the contents of the chamber to UV light to inhibit bacteria/fungi growth; additionally, UV light elevates glucosinolates 17. (optional) introduce antibiotics to the chamber to inhibit bacteria/fungi growth

18. (optional) introduce flavor enhancers, preservatives, nutrients or growth regulators to the chamber to enhance product characteristics

19. (optional) introduce fiber-optic/Green Fluorescent biop robes to the chamber to detect food-borne contaminates

20. sparge with oxygen to prevent anaerobiosis and promote germination

21. (optional) greening option 1: illuminate the contents of the chamber in- situ, and optional add carbon dioxide

22. drain the chamber 23. unseal the chamber

24. harvest the sprouts

25. (optional) greening option 2: illuminate the sprouts with high intensity light

26. wash the sprouts

27. package the sprouts An apparatus and method for continuously producing sprouts according to an alternative embodiment of the present invention will now be described with respect to Figures 9 and 10.

The apparatus and method for continuously producing sprouts are similar to those of producing batches of sprouts (the same reference numerals are used for the same features), except that the chamber 12 is divided into lower and upper sub-chambers by a floor sieve 50. The floor sieve 50 functions comparably to the fixture 44b that is sized for passing only seed hulls with the growing medium. As seed hulls become water-logged in the upper sub-chamber 12b, they move down, through the openings in the floor sieve 50, into the lower sub-chamber 12a. According to a preferred embodiment of the present invention, the openings in the floor sieve 50 are 3-4 mm, sufficient to pass seed hulls with negligible sprout loss. Alternatively, a floor sieve 50' may have variable size openings. As shown in Figure 10, a pair of substantially congruent plates having normally aligned openings may be rotatably mounted with respect to one another. By rotating the top plate 52 with respect to the bottom plate 54, the size of the openings in the floor sieve 50' are defined by the aligned portions of the openings in each respective plate. A valve 56 is opened periodically to purge the accumulation of seed hulls in the lower sub-chamber 12a.

Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative devices, shown and described herein. Accordingly, various modifications may be made without departing from the spirit and scope of the general inventive concept as defined by the appended claims and their equivalents.

Claims

WE CLAIM;

1. A method of growing sprouts, said method comprising: adding seeds to a chamber; flooding said chamber with a combination of a sterilant and a surfactant; rinsing said seeds in said chamber with at least one charge of sterile water to remove said combination of said sterilant and said surfactant; adding a fresh charge of said sterile water to said chamber; continuously recharging said chamber with sterile water for hydrating said seeds; sparging said chamber with a lifting fluid for preventing anaerobiosis and for promoting germination of said seeds into sprouts; and harvesting said sprouts.

2. The method according to claim 1, further comprising: controlling a temperature of said sterile water via a heat exchanger

3. The method according to claim 2, wherein said heat exchanger is in said chamber.

4. The method according to claim 1, further comprising: washing said sprouts; and packaging said sprouts.

5. The method according to claim 4, further comprising: drying said sprouts.

6. The method according to claim 5, wherein said drying includes centrifuging said sprouts.

7. The method according to claim 1, further comprising: treating said chamber for inhibiting contamination.

8. The method according to claim 7, wherein said treating said chamber includes pre-treating with peroxide vapor.

9. The method according to claim 7, wherein said treating said chamber includes continuous exposure to ultraviolet light.

10. The method according to claim 1, further comprising: pre-treating said seeds before said adding said seeds to said chamber.

11. The method according to claim 10, wherein said pre-treating said seeds includes irradiating said seeds with γ-radiation for reducing contamination.

12. The method according to claim 10, wherein said pre-treating said seeds includes mechanically sorting said seeds for removing damaged seeds.

13. The method according to claim 10, wherein said pre-treating said seeds includes exposing said seeds to peroxide vapor for inhibiting contamination.

14. The method according to claim 1, further comprising: pre-treating said sterile water for inhibiting contamination.

15. The method according to claim 14, wherein said pre-treating said sterile water includes ozonating said sterile water.

16. The method according to claim 14, wherein said pre-treating said sterile water includes chlorinating said sterile water.

17. The method according to claim 1, wherein said continuously recharging said chamber with sterile water for hydrating said seeds includes recirculating said sterile water.

18. The method according to claim 1, further comprising: exposing said seeds, said sterile water, and said sparging gas to ultraviolet light for inhibiting bacteria and fungi growth.

19. The method according to claim 1, further comprising: exposing said seeds to ultraviolet light for elevating glucosinolates in said sprouts.

20. The method according to claim 1 , further comprising: introducing antibiotics to said chamber for inhibiting bacteria and fungi growth.

21. The method according to claim 1, further comprising: introducing at least one of a flavor enhancer, a preservative, a nutrient, and a growth regulator to said chamber for enhancing product characteristics of said sprouts.

22. The method according to claim 1, further comprising: introducing Green Fluorescent bioprobes to said chamber for detecting food-borne contaminates

23. The method according to claim 1, further comprising: agitating mechanically the contents of said chamber for uniform exhausting of said sterilant.

24. The method according to claim 1, further comprising: illuminating said seeds in said chamber for enhancing said sprouts' color.

25. The method according to claim 1, further comprising: adding carbon dioxide to said sparging oxygen.

26. The method according to claim 1, wherein said fluid includes oxygen.

27. The method according to claim 26, wherein said fluid is a mixture of oxygen and sterile water.

28. The method according to claim 1, wherein said fluid includes air.

29. The method according to claim 28, wherein said fluid is a mixture of air and sterile water.

30. An apparatus for germinating seeds in a growing medium and for harvesting sprouts germinated from the seeds, the apparatus comprising: a chamber adapted for receiving the seeds; a chamber inlet adapted for ingress of the growing medium into said chamber; a chamber outlet adapted for egress of the growing medium and sprouts out of said chamber, said chamber outlet having interchangeable separating fixtures, said interchangeable separating fixtures including: a first fixture adapted for passing the growing medium out of said chamber and adapted for retaining the sprouts in said chamber, and a second fixture adapted for passing the growing medium out of said chamber and adapted for passing the sprouts out of said chamber; and a sparger adapted for dispensing a lifting fluid into said growing medium.

31. The apparatus according to claim 30, further comprising: a heat exchanger adapted for regulating growing medium temperature.

32. The apparatus according to claim 30, further comprising: a source of ultraviolet light in said chamber.

33. The apparatus according to claim 30, further comprising: at least one of an ozonator and a chlorinator adapted for treating the growing medium.

34. The apparatus according to claim 30, wherein said interchangeable separating fixtures further include a third fixture adapted for passing the growing medium and hulls from the seeds out of said chamber, and adapted for retaining the sprouts in said chamber.

35. The apparatus according to claim 30, further comprising: a pump connected between said chamber inlet and said chamber outlet and adapted for recirculating the growing medium through said chamber.

36. The apparatus according to claim 30, wherein said chamber has a height to diameter ratio equal to or greater than 3.

37. The apparatus according to claim 36, wherein said height to diameter ratio is equal to or greater than 4.

38. The apparatus according to claim 30, wherein said sparger includes a first dispenser proximate to a lower end of said chamber and a second dispenser proximate to an upper end of said chamber.

39. The apparatus according to claim 30, further comprising: a closure substantially sealing said chamber; a feed adapted for supplying the lifting fluid to said sparger, said feed connecting a lifting fluid source outside said chamber to said sparger inside said chamber; and a vent adapted for passing the lifting fluid out of said chamber.

40. The apparatus according to claim 30, further comprising: a screen dividing said chamber into a lower sub-chamber and an upper sub-chamber, said screen being adapted for passing hulls from the seeds from said upper sub-chamber to said lower sub-chamber, and said upper sub-chamber containing said sparger.

41. The apparatus according to claim 40, further comprising: a valve adapted for purging the seed hulls from said lower sub-chamber.