WO2001060182A1

WO2001060182A1 - Enzymatic processing of biomass to produce edible products

Info

Publication number: WO2001060182A1
Application number: PCT/US2001/004652
Authority: WO
Inventors: Ronald H. Lane
Original assignee: Lipogenics, Inc.
Priority date: 2000-02-15
Filing date: 2001-02-13
Publication date: 2001-08-23
Also published as: AU2001238225A1; CN1423531A

Abstract

This invention relates to novel processes for treating biomass utilizing enzymatic digestion to separate the constituents of biomass. These processes advantageously bypass several expensive, time-consuming and potentially hazardous conventional biomass processing steps. The processes of this invention may be used to produce a variety of useful and valuable biomass-derived products, including biomass oil, biomass grate, biomass protein and biomass juice.

Description

ENZYMATIC PROCESSING OF BIOMASS TO PRODUCE EDIBLE PRODUCTS

TECHNICAL FIELD OF THE INVENTION This invention relates to novel processes for treating various types of biomass. The processes of this invention utilize aqueous enzymatic digestion to separate the constituents of biomass.

RELATED APPLICATIONS This application is related to and claims priority from provision patent application serial no. 60/182,451.

BACKGROUND OF THE INVENTION Conventional processing of biomass typically follows a multi-step procedure that generates undesirable waste products and tends to degrade certain constituents of the biomass. Specialized equipment is required for these processing steps, often making the overall process quite expensive. In addition, many of these conventional processing steps are arduous and time-consuming and also produce large volumes of waste effluent.

Accordingly, there remains a need for new processes for treating biomass that can generate multiple food grade and value-added ingredients, including protein, soluble fiber, aqueous-soluble micronutrients and high grade edible oil, without the disadvantages of conventional biomass processing.

SUMMARY OF THE INVENTION

The novel processes of this invention meet the unmet need for improved biomass processing technology. By utilizing aqueous enzymatic digestion to separate the constituents of biomass, the novel processes of this invention bypass several expensive, time-consuming and potentially environmentally damaging conventional biomass processing steps. The processes of this invention may be used to produce a variety of useful and valuable biomass- derived products, including biomass oil, biomass grate, biomass protein and biomass juice. The processes of this invention include treating a biomass slurry with an enzyme(s) and then separating the enzymatic products into at least an oil phase, an aqueous phase and a solid phase. It is an objective of this invention that the products of these three phases are edible without further treatment. The processes of this invention also include purifying the oil phase. Furthermore, the processes of this invention include separating the aqueous phase into a recyclable water product and a biomass juice concentrate, and separating the solid phase into a biomass grate product and a biomass protein product. It is also a further objective that the recyclable water product, the biomass juice concentrate, the biomass grate product and the biomass protein product are edible without further treatment. Other objectives of this invention will be apparent from the detailed description of the invention that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart depicting the processes of this invention.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the following definitions apply (unless expressly noted to the contrary):

"Edible" refers to matter that may be consumed by humans without significant deleterious health consequences.

"Biomass" refers to the flowers, stalks, leaves, roots, stems (including tubers) and fruit

(including the skin, flesh and seeds) for at least one plant selected from the group consisting of the following: palm, banana, sugar cane, sugar beet, orange, grapefruit, potato, apple or grape. The processes of this invention preferably use raw biomass. However, dried biomass or defatted biomass may also be used.

"Defatted biomass" refers to biomass that has undergone a process such as pressing (e.g., by an expeller press) to remove a significant portion of the oil from the biomass.

"Effective particle size" refers to biomass having an average particle size that enables the enzyme(s) to catalyze the necessary chemical reactions of the invention. "Effective quantity of water, duration, pH and temperature" refer to the values of these substances or conditions where the enzyme(s) is able to perform the necessary chemical reactions of the invention. Furthermore, in the processes of this invention, individual values of particle size, amount of water, duration, pH and temperature should be considered in relation to the values of the other treatment parameters, including the amount and nature of enzyme being used. Although this application provides guidance as to how such values should be evaluated, and sets forth particular values for certain preferred processes of this invention, it is well within the skill of the art to alter the conditions and select other appropriate parameters without undue experimentation. When no specific values are indicated, a value representing an effective parameter is to be presumed.

"Biomass slurry" refers to a mixture of biomass and water.

"Enzyme" refers to a type of protein molecule that acts as a biochemical catalyst.

"Enzymatic product slurry" refers to a mixture of biomass-derived products obtained as a result of the enzymatic treatment of biomass.

"Oil phase" refers to a product obtained by separating the enzymatic product slurry. Although this phase may contain solutes, particulate matter and water, it contains less of these substances than the solid phase and the aqueous phase. The "oil phase" primarily contains edible oil.

"Aqueous phase" refers to a product obtained by separating the enzymatic product slurry. Although this phase may contain solutes (e.g., protein molecules), particulate matter and oil, it contains less of these substances than the solid phase and the oil phase. The "aqueous phase" contains at least edible biomass juice and recyclable water.

"Solid phase" refers to a product from separating the enzymatic product slurry. Although this phase may contain some liquid when isolated, it contains less liquid (i.e., water or oil) than the aqueous phase and the oil phase. The "solid phase" contains at least edible biomass grate and biomass protein.

"Purifying" refers to the process of removing some, if not all, impurities from a substance. After purification, some impurities may remain.

"Recyclable water product" refers to a product obtained by separating the aqueous phase. Although this product may contain some solutes, particulate matter, or oil, it contains less of these substances than the biomass juice concentrate. The "recyclable water product" is primarily water of a quality (dictated by industrial efficiency and environmental regulatory standards) that may be combined with biomass in order to form the biomass slurry. Used in this way, it results in pollution abatement by reducing or eliminating an effluent (waste) stream.

"Biomass juice concentrate" refers to a product obtained by separating the aqueous phase. This product is a combination of at least water, and biomass protein. Depending on which process is used to separate the aqueous phase, the "biomass juice concentrate" may also contain constituents that produce a sweet and/or fragrant quality. When the biomass juice is used as a ready-made beverage, these later qualities are especially desirable.

"Biomass grate product" refers to a product obtained by separating the solid phase. Although this product may contain oil, water, and biomass protein product, it primarily contains biomass fiber (e.g., cellulose) which remains undissolved during an alkaki extraction procedure.

"Biomass protein product" refers to a product obtained by separating the solid phase. Although this product may contain oil, water, and biomass grate product, it primarily contains protein molecules. "Vacuum drying" refers to a procedure that removes moisture from a biomass product by heating the biomass product at a temperature greater than ambient temperature, and at a pressure less than normal atmospheric pressure (101.3 KPa absolute).

"Short path distillation" refers to the procedure of using a short path distillation apparatus that vaporizes a liquid mixture with the subsequent collection of components by differential cooling to condensation.

"About" refers to a range of +/- 5%, with the exception of pH. For example, "about 10 microns" is equivalent to "9.5 microns to 10.5 microns." When used in relation to pH,

"about" refers to a range of +/- 0.2. For example, "a pH of about 10" is equivalent to "a pH of 9.8 to 10.2."

"Free fatty acids" refers to fatty acid molecules that have a free carboxyl group, that is they are not glycerol esters.

"Membrane separation procedure" refers to any procedure that in part uses a membrane that is at least permeable for water, but may be impermeable for molecules larger than water such as protein, or carbohydrate molecules.

"Ultrafiltration" refers to a membrane separation procedure that is pressure driven and whose membrane is permeable to water, inorganic salts, and small organic molecules (e.g., glucose), but impermeable to macromolecules (e.g., albumin protein).

"Reverse osmosis" refers to a membrane separation procedure that is pressure driven such that flow takes place from the higher concentration side of the membrane to the lower concentration, and whose membrane is permeable to water and micro-organic molecules (e.g., ethyl alcohol), but impermeable to macromolecules (e.g. albumin protein), inorganic salts, and some forms of non-ionic organic compounds (e.g., fructose). "Raw biomass" refers to fresh biomass (e.g., has not been dried or defatted).

"Average particle size" refers to the arithmetic mean diameter of a sample of particles.

"Pectinases" refer to enzymes that catalyze the hydrolysis of pectin.

"Cellulases" refer to enzymes that catalyze the hydrolysis of cellulose.

"Hemicellulases" refer to enzymes that catalyze the hydrolysis of hemicellulose.

"Carbohydrases" refer to enzymes that catalyze the hydrolysis of carbohydrates.

"Gravity phase separation" refers to a procedure for separating phases of a product based upon the specific gravity of each phase.

"Centrifugation" refers to a procedure using centrifuged force to separate phases based upon the specific gravity of each phase.

"Protein separation procedure" refers to any process that separates protein molecules from water, other biomolecules such as lipids, or other protein molecules. For example, the process of this invention may separate protein molecules according to their size, binding specificity, charge, or solubility.

"Protein solubilization procedure" refers to a procedure whereby a liquid containing undissolved protein molecules is treated until the protein molecules are substantially soluble in the liquid.

"Alkali extraction" refers to a procedure using a solution with a basic pH to extract protein molecules from a solid. "Dilute" refers to a solution concentration of less than five molar.

"Isoelectric precipitation procedure" refers to a procedure whereby the pH of a solution containing dissolved protein molecules is decreased in order to precipitate the protein molecules.

Individual preferred values of various process parameters (including, but not limited to, average biomass particle size, temperature, pH, type of enzyme and enzyme treatment duration) apply individually to particular process steps, but can also be applied in combination with other process steps.

The processes of this invention use biomass having an effective particle size as the starting material. This starting material can be obtained from raw, dry or defatted biomass. If defatted biomass is used, the processes of this invention will yield little biomass oil.

To promote effective enzymatic digestion, the average biomass particle size may be reduced by grinding or sliredding. Reducing the particle size in tins manner may facilitate the enzymatic treatment. Typically, the reduction process is performed by using a food grade mill (e.g., a Szego mill). The average particle size for the processes of this invention is preferably between about 0.1 and about 50 microns; more preferably, between about 1 and about 15 microns; and most preferably, about between 5 and about 10 microns. The most favorable average particle size may depend on the particular process conditions, and can readily be determined by those of ordinary skill in the art without undue experimentation.

The enzymatic treatment is more productive with the addition of water to the biomass. Water may be combined with the biomass before, during or after the reduction process. Since heat may be produced during the reduction process, the most preferred embodiment of this invention includes introducing the water prior to the reduction process in order to minimize thennal damage to the heat sensitive constituents of the biomass (e.g., biomass proteins). The addition of water to biomass with an effective particle size results in a biomass slurry. Preferably, the biomass slurry comprises about 1 part biomass to between about 1 and about 20 parts water (w/v); more preferably, about 1 part biomass to between about 5 and about 10 parts water; and, most preferably, about 1 part biomass to about 10 parts water. If desired, the water temperature can be adjusted prior to its addition. In a preferred embodiment, the water is used at room temperature or heated prior its addition. Preferably, the water is between about 23 °C and about 60°C; more preferably, between about 23 °C and 40°C; and, most preferably, at about 35°C. The temperature and pH of the biomass slurry may be adjusted to provide effective conditions for enzymatic treatment. Depending on the type of enzyme being used, and other treatment parameters, the pH and temperature may be adjusted before or after addition of the enzyme in order to meet the enzyme supplier's recommendation. In a preferred embodiment the biomass slurry is heated prior to addition of the enzyme. The temperature of the biomass slurry is preferably between about 23°C and about 75°C; more preferably, between about 40°C and about 65°C; and, most preferably, at a temperature of about 50°C. In another preferred embodiment, the pH of the biomass slurry is adjusted prior to addition of the enzyme to between about 3 and about 6.5; more preferably, between about 4 and about 5.5; and, most preferably, to about 4.5. To achieve these reduced preferred pH values, any suitable acid may be used. The preferred acids for this purpose are food grade acids, such as food grade phosphoric acid.

Once the biomass slurry has been prepared, it is subjected to enzyme treatment. There are several types of commercially available enzymes that can be used effectively in the processes of this invention. Typically, these enzymes are those recommended by their manufacturers to degrade cellular structures of plant materials, such as the cell wall tissues that contain the biomass oil (e.g., cellulose and hemicellulose.) Individual enzymes may be used alone or combined with other effective enzymes to produce a particular desired result. Preferred types of enzymes for use in the processes of this invention include, pectinases, carbohydrases, cellulases, hemicellulases and combinations thereof. A combination of pectinases, carbohydrases, cellulases, and hemicellulases is particularly preferred. Specific enzymes for use in the processes of this invention include Pectinex 3xL (a pectinase), SP-249 (a carbohydrase), Celluclast 1.5L (a cellulase) and Gamanase (a hemicelmlase). These four particular enzymes are available commercially from Novo Nordisk (Denmark). Gamanase is a most preferred enzyme for the processes of this invention. The effective enzyme amount and effective temperature, pH and enzyme treatment time should be selected so as to facilitate enzymatic digestion. Individual values will largely depend on the type of enzyme being used and the values set for other enzyme treatment parameters. The enzyme manufacturers typically provide considerable guidance in this regard. In a preferred embodiment, the amount of enzyme is about 0.1 % to about 5% of the biomass by weight; more preferably, about 1% to about 3%, and most preferably, about 2%. The enzymatic treatment can be carried out in any suitable vessel (e.g., an agitation tank). The preferred enzymatic treatment duration is equivalent to the time when the oil yield of the process is equivalent, or almost equivalent, to the oil content of the biomass. Depending on the treatment parameters and the type of enzyme(s), typically the enzyme treatment duration will be between about 3 and about 36 hours. Preferably the treatment duration will be between about 5 and about 30 hours; more preferably, between about 7 and about 24 hours; and, most preferably, about 20 hours. During the treatment time, there may be a period of agitation followed by a period of non-agitation (which can take place in the same or a different vessel, such as a settling tank). For example, once the enzyme is added, the enzymatic slurry maybe maintained at an elevated temperature (e.g., about 50°C) for about 5 hours with agitation, followed by about 15 hours of non-agitation at the same temperature. During the enzymatic treatment, the biomass of the biomass slurry is degraded into its constituent parts, resulting in the enzymatic product slurry. At this time, the oil yield of the enzymatic product slurry is monitored in order to assess the progress of the treatment. Once the oil yield of the enzymatic product slurry is close to the oil content of the biomass starting material, the treatment is discontinued.

Following enzyme treatment, the components of the enzymatic product slurry can be separated. Although many separation techniques can be used for this portion of the process, gravity phase separation is preferred (e.g., gravity settling or centrifugation). Most preferably, separation is performed by centrifugation. The centrifuge parameters may be readily determined by those of ordinary skill in the art. An industrial centrifuge will likely be effective with a setting of 3000-6000 X g. Using a laboratory centrifuge, on the other hand, it has been found that using an IEC fixed head rotor at about 9000 X g is effective. At least three phases should result from the separation procedure: (1) a solid phase, (2) an aqueous phase, and (3) an oil phase. The efficiency of the separation procedure is analytically determined by the cross-contamination of the phases. The separation procedure may also produce an emulsion phase. It is an object of this invention to reduce or eliminate the existence of this phase. Typically, the emulsion phase contains a mixture of oil and water that is stabilized by soluble surfactive proteins. By heating or adding an acidic solution to the emulsion layer the layer is separated into oil and water. The resultant aqueous and oil layers can then be added to the previously obtained aqueous and oil phases, respectively. The following sections detail further characterization and treatment options for each of the three primary phases that are separated from the enzymatic product slurry.

Oil Phase

The biomass oil in the oil phase is of considerable quality. Since the enzyme treatment is relatively gentle to the biomass constituents, including the oil, the oil can be consumed without further treatment. For this reason, the biomass oil obtained is superior to conventional industry produced RBD (refined, bleached and deodorized) biomass oil as it retains its natural flavor and fragrance. Furthermore, the enzymatic treatment results in a recovery percentage that is comparable to conventional industry procedures.

Although the enzymatic treatment produces high quality biomass oil, the oil phase may be purified to yield a better product. After the separation of the enzymatic product slurry, the oil phase may have about 2% moisture content. This residual moisture can be reduced through vacuum drying to preferably less than about 1.0 %, and most preferably about 0.1% water by weight. This additional step helps to reduce hydrolysis of neutral triglycerides. Also, the oil phase may be subjected to short path distillation which removes free fatty acids to preferably less than about 2 %, and most preferably about 0.5% of the oil phase by weight.

Aqueous Phase The aqueous phase obtained from the separation of the enzymatic product slurry retains a pronounced, pleasant biomass aroma, a somewhat sweet flavor and low viscosity, and may be consumed directly without further treatment. This phase typically contains a high percentage of the protein from the biomass if the pH of the biomass slurry was below about 5. The protein is solubilized in the aqueous phase under such conditions.

Although the aqueous phase may be consumed without further treatment, this phase may be separated into at least a recyclable water product and a biomass juice concentrate. By performing this further treatment of the aqueous phase, the concentration of the protein, as well as other desirable constituents of the aqueous phase, can be increased and retained in the biomass juice concentrate. Conventional concentration techniques known to those of skill in the art, such as freeze-drying, can be used. Preferably a membrane separation procedure is used, such as ultrafiltration or reverse osmosis, although ultrafiltration may result in a loss of aroma. Reverse osmosis is preferred for industrial-scale processing. It may be desirable to pasteurize the aqueous phase before it is separated, or the biomass juice concentrate after separation.

It is a further objective of this invention to produce a recyclable water product from the aqueous phase. Typically, the recyclable water product will retain some impurities, such as residual carbohydrate and protein molecules. However, by using the processes of the present invention, the amount of impurities will be reduced and the quality of the recyclable water product will be high enough so that it may be reused. In other words, the recyclable water product may be used as the input water at the beginning of the process (see Fig. 1). As a result of the in-process recycling of the water used, this invention prevents or reduces the effluent water produced by the enzymatic treatment of biomass. The potential benefits from this segment of the process include cost savings, reduced legal liability, and improved corporate image.

Solid Phase

The solid phase obtained from separation of the enzymatic product slurry is edible. If desired, however, the solid phase can be further processed to obtain biomass grate product and biomass protein product. To separate these components, any conventional protein separation technology can be used. Preferably, alkali extraction is first used to solubilize the proteins. In this preferred embodiment, the protein molecules of the solid phase are extracted into an aqueous alkali solution at an effective pH, typically between about 9 and about 12.5; more preferably, between about 10 and about 12; and most preferably, between about 11 and about 12. Any effective alkali solution may be used, including sodium hydroxide, and potassium hydroxide. Dilute sodium hydroxide is preferred. Typically, water is first added to the solid phase at a ratio of about 1 part solid phase to about 10 to about 20 parts water (w/v); and preferably at a ratio of about 1 part solid phase to about 15 parts water. Then, the alkali solution is added to raise the pH of the solid phase/water combination to the effective pH. Additional volumes of the alkali solution may be added during the alkali extraction to maintain the pH of the solid phase/water combination at the effective pH. This alkali extraction solubilizes a substantial percentage of the protein in the solid layer. Once the protein has been solubilized, the filtrate (containing the solubilized protein) can then be acidified to precipitate the protein. This isoelectric precipitation procedure is typically carried out using an aqueous acid solution at a pH of between about 4 and about 6; preferably, between about 4 and about 5; and, most preferably, at a pH of about 4.5. The precipitated protein tends to be off-white in color and substantially free from any biomass aroma. This protein precipitate can be isolated by any conventional method. Centrifugation is preferred. The separation of the solid phase also results in a biomass grate product which has a high plant fiber content. The biomass grate product is edible without further treatment, but may be dried using any suitable methods in order to produce a more commercially viable product. For example, a spray drying method may be used.

Without wishing to be bound by theory, the enzyme or enzymes used in the processes of this invention break down the tissue structure of biomass such that the oil stored in these structures is released. As a result, the biomass oil can be effectively separated from the remaining biomass constituents without harsh, conventional processing steps, such as pressing or volatile solvent extraction. Furthermore, the enzymatic treatment described herein is sufficiently mild to allow for the effective recovery of other biomass constituents, such as biomass protein, biomass grate and biomass juice concentrate. As a result, the processes of this invention provide an economical and potentially integrated method for the complete utilization of biomass.

Although it is an object of this invention that the biomass-derived products obtained using the processes of this invention can be used as food grade ingredients without further processing, they may also be used in animal feed, or industrial applications. For example, the biomass oil obtained using the processes of this invention is food grade, and may be incorporated into edible products (such as cooking oil, baking ingredients or flavorizers). Alternatively, the biomass oil can also be used for industrial applications, such as detergents, soaps, creams and shampoos. Furthermore, the other biomass derived products (including biomass grate product, biomass protein product, biomass juice concentrate and recyclable water product) recoverable using the processes of this invention can also be used directly as food grade material and incorporated into edible products. For example, these biomass-derived products can be used in a host of nutritious foodstuffs (such as nature bars, drinks and drink mixes). Although many other uses of these products will be evident to those of ordinary skill in the art, the use of the biomass grate product as a high fiber alternative to bran and other fiber-rich material is of specific interest. Also, since the biomass protein product recoverable using the processes of this invention has a high protein content, it might be used as an alternative to soy protein. Such applications include, without limitation, meat extenders, processed foods, health foods, sport drink mixes, baby foods and baked goods.

While we have described a number of embodiments of this invention, it is apparent that our basic constructions may be altered to provide other embodiments that utilize the formulations and methods of this invention. Such embodiments are considered within the scope of the invention. Other embodiments are contained in the following claims.

Claims

What is claimed is:

1. A process for producing edible biomass products comprising: combining biomass, with an effective particle size, with an effective quantity of water to produce a biomass slurry; treating the biomass slurry with at least one enzyme for an effective duration and at an effective pH and temperature to produce an enzymatic product slurry; and, separating the enzymatic product slurry into at least an oil phase, an aqueous phase and a solid phase.

2. The process of claim 1, comprising purifying the oil phase.

3. The process of claim 1, comprising separating the aqueous phase to produce at least a recyclable water product and a biomass juice concentrate.

4. The process of claim 1, comprising separating the solid phase into at least a biomass grate product and a biomass protein product.

5. The process of claim 2, wherein the purification procedure is vacuum drying.

6. The process of claim 2, wherein the purification procedure is short path distillation.

7. The process of claim 6, wherein the oil phase after purification comprises less than about 0.5% of free fatty acids by weight.

8. The process of claim 6, wherein the oil phase after purification comprises less than about 0.1% of free fatty acids by weight.

9. The process of claim 5, wherein the oil phase after purification comprises less than about 0.5% of water by weight.

10. The process of claim 5, wherein the oil phase after purification comprises less than about 0.1% of water by weight.

11. The process of claim 3, wherein the effective quantity of water is taken from the recyclable water product.

12. The process of claim 3, wherein separating the aqueous phase is performed using a membrane separation procedure.

13. The process of claiml2, wherein the membrane separation procedure is ultrafiltration.

14. The process of claim 12, wherein the membrane separation procedure is reverse osmosis.

15. The process of claim 1 , wherein the biomass is from raw biomass.

16. The process of claim 1 , wherein the biomass has an average particle size of about 10 microns.

17. The process of claim 1, wherein the biomass slurry comprises about 1 part biomass and between about 1 to about 20 parts water.

18. The process of claim 1, wherein the biomass slurry comprises about 1 part biomass and between about 5 to about 10 parts water.

19. The process of claim 1, wherein the pH is between about 4 to about 6.

20. The process of claim 1, wherein the enzyme is at least about 0.1% to about 3% of the biomass by weight.

21. The process of claim 1 , wherein the enzyme is about 2% of the biomass by weight.

22. The process of claim 1, wherein the temperature is between about 25°C and about 75°C.

23. The process of claim 1, wherein the duration is between about 3 and about 24 hours.

24. The process of claim 1, wherein the duration is about 15 hours.

25. The process of claim 1, wherein the enzyme is selected from the group consisting of pectinases, cellulases, hemicellulases, carbohydrases and mixtures thereof.

26. The process of claim 1, wherein the enzyme is a hemicellulase.

27. The process of claim 1, wherein the enzymatic product slurry is separated by a gravity phase separation.

28. The process of claim 27, wherein the gravity phase separation is centrifugation.

29. The process of claim 4, wherein the separation of the solid phase is performed by a protein separation procedure.

30. The process of claim 29, wherein the separation of the solid phase is performed by a protein solubilization procedure.

31. The process of claim 30, wherein the protein solubilization procedure is an alkali extraction.

32. The process of claim 31 , wherein the alkali extraction is performed at a pH of about 11 to about 12.

33. The process of claim 31, wherein the alkali extraction comprises using a dilute sodium hydroxide solution.

34. The process of claim 4, wherein the biomass grate product is dried to contain less than about 6% water by weight.

35. The process of claim 4, comprising an isoelectric precipitation procedure.

36. The process of claim 35, wherein the isoelectric precipitation procedure is performed at apH of between about 4 and about 5.

37. The process of claim 4, wherein the biomass protein product represents at least about 5% of total protein content of the biomass.

38. The process of claim 4, wherein the biomass protein product represents at least about 10% of total protein content of the biomass.

39. The process of claim 3, comprising treating the biomass juice concentrate with an isoelectric precipitation procedure.

40. The process of claim 3, comprising treating the biomass juice concentrate with an alkali solubilization procedure and an isoelectric precipitation procedure.

41. The process of claim 4, comprising an alkali solubilization procedure and an isoelectric precipitation procedure.

42. The process of claim 40 or 41, wherein the alkali solubilization procedure is performed at a pH of about 11 to about 12, and the isoelectric precipitation procedure is performed at a pH of between about 4 and about 5.