Bioconversion of agricultural wastes into proteinaceous animal feed

• US 4,526,791 A
• Filed: 12/23/1982
• Issued: 07/02/1985
• Est. Priority Date: 01/30/1979
• Status: Expired due to Fees

• Current Assignee: University of Waikato
• Original Assignee: University of Waikato
• Inventors: Young, Murray M.
• Primary Examiner(s): Penland, R. B.
• Application Number:
  US06/452,515
• Time in Patent Office: 922 Days
• Field of Search: 435/68, 435/251, 435/252, 435/911, 426/2, 426/53, 426/56, 426/59, 426/623, 426/630, 426/635, 426/636, 426/807
• US Class Current: 426/53
• CPC Class Codes: A23K 10/12 by fermentation of natural products, e.g. of vegetable material, animal waste material or biomass
• CPC Class Codes: C12N 1/22 Processes using, or culture media containing, cellulose or hydrolysates thereof
• CPC Class Codes: C12P 5/023 Methane
• CPC Class Codes: Y02E 50/30 Fuel from waste, e.g. synthetic alcohol or diesel
• CPC Class Codes: Y02P 60/87 Re-use of by-products of food processing for fodder production
• CPC Class Codes: Y02W 30/40 Bio-organic fraction processing; Production of fertilisers from the organic fraction of waste or refuse
• CPC Class Codes: Y10S 426/807 Poultry or ruminant feed
• CPC Class Codes: Y10S 435/911 using fungi

Abstract

Agricultural waste material, including animal manure and crop wastes, are converted into proteinaceous animal feed products by a fermentation process using the fungus, Chaetomium cellulolyticum.

Claims

1. A process for the formation of proteinaceous material from agricultural waste, which consists of:

(a) anaerobically digesting animal manure to form a gaseous product containing methane and a sludge containing nitrogen and consisting of liquid and solid phases, said anaerobic digestion being effected under mesophilic or thermophilic anaerobic fermentation conditions,

(b) pretreating a crop residue in particulated form with a dilute aqueous solution of sodium hydroxide to form a slurry of the pretreated crop residue in solid form and spent sodium hydroxide solution, said pretreatment being effected either;

(i) using an aqueous sodium hydroxide solution at a concentration of about 0.25 to about 1.0% W/W NaOH at a temperature of about 60°

to 121°

C. for a time of about 120 to about 15 minutes, or

(ii) using an aqueous sodium hydroxide solution at a concentration of about 3 to about 6% W/W NaOH at a temperature of about 15°

to about 30°

C. while being subjected to gamma radiation at a dosage level of about 10 to about 50 megarads for a time of about 120 to about 60 minutes;

(c) mixing the sludge formed in step (a) with the slurry formed in step (b) without separating any component therefrom to form a fermentation medium having a solids concentration of up to about 30% W/W and containing sufficient nutrient elements to effect fungal fermentation;

(d) sterilizing said fermentation medium and adjusting the pH of the resulting sterile fermentation medium to a value within the range of about 5 to about 7 if not already at a pH value within said range;

(e) inoculating said sterile fermentation medium with a culture of the fungus Chaetomium cellulolyticum;

(f) aerobically fermenting said fungus in the sterile inoculated fermentation medium formed in step (e) at a temperature of about 30°

to about 40°

C. for a time sufficient to provide a fermented solid mass consisting of about 20 to about 100% DM of the fungus and any balance of unfermented crop residue; and

(g) separating said solid mass formed in step (f) from the fermentation medium.

2. The process of claim 1 wherein said anaerobic fermentation is effected under mesophilic fermentation conditions of about 30°

to about 40°

C. for about 10 to about 14 days.

3. The process of claim 1 wherein said anaerobic fermentation is effected under thermophilic fermentation conditions of about 50°

to about 60°

C. for about 8 to about 10 days.

4. The process of claim 1 wherein said fermentation step (f) is effected to provide a fermented solid mass consisting of about 20 to about 80% DM of the fungus and the balance of unfermented crop residue.

5. The process of claim 4 including the additional step of drying the solid phase separated in step (g) below about 10% W/W.

6. The process of claim 4 wherein the residual fermentation medium remaining after separation of the solid phase in step (g) is recycled to the anaerobic digester step (a) and/or to the pretreatment step (b).

7. The process of claim 1 wherein the crop residue is selected from the group consisting of cereal grain straws and bagasse.

8. The process of claim 7 wherein the cereal grain straw is cornstover.

9. The process of claim 7 wherein the cereal grain straw is wheat straw.

10. The process of claim 1 wherein the fermentation medium used in step (f) additionally contains about 0.01 to about 0.3% W/V of a carboxy polymethylene.

11. The process of claim 1 wherein said pretreatment step (b) is effected at a temperature of about 120°

C. for about 20 minutes using 0.5% W/V NaOH solution.

12. The process of claim 1 wherein said pretreatment step (b) is effected at a temperature of about 25°

C. for about 120 minutes or an applied gamma radiation of 10 megarads using about 4% W/W NaOH solution.