Enzymatic hydrolysis of old corrugated cardboard (OCC) fines from recycled linerboard mill waste rejects

• US 9,951,363 B2
• Filed: 03/13/2015
• Issued: 04/24/2018
• Est. Priority Date: 03/14/2014
• Status: Active Grant

• Current Assignee: The Research Foundation for The State University of New York (State University of New York)
• Original Assignee: The Research Foundation of State University of New York
• Inventors: Min, Byeong Cheol, Bhayani, Bhavin V., Ramarao, Bandaru V.
• Primary Examiner(s): Kim, Alexander D
• Application Number:
  US14/656,988
• Publication Number:
  US 20150259719A1
• Time in Patent Office: 1,138 Days
• CPC Class Codes: C12P 19/02 Monosaccharides 2-ketogulonic acid C12P7/60
• CPC Class Codes: C12P 19/14 produced by the action of a carbohydrase (EC 3.2.x), e.g. by alpha-amylase , e.g. by cellulase, hemicellulase
• CPC Class Codes: C13K 1/02 obtained by saccharification of cellulosic materials manufacture of fodder A23K10/32

Abstract

A significant fraction of short fibers (fines) is produced while recycling Old Corrugated Containerboards (OCC), which are usually rejected as solid waste stream, requiring landfilling and posing environmental problems. The major component of these fines rejects are primarily cellulose that can be hydrolyzed into sugars for possible fermentation into biofuels, bioplastics or other sugar based products. Use of fines also offers benefits such as negative costs and production of fermentable sugars without requiring complex pretreatment processes, now required to hydrolyze and eliminate inhibitors from hydrolyzate. Enzymatic hydrolysis of reject fines from a recycled OCC mill, employing different strains of cellulases, were investigated. Fillers (up to 30 mass %) in the fines increases the required dosage of enzymes and costs. Enzyme loading can be lowered by addition of surfactants to reduce their inhibitory activity. The nonionic surfactant Triton X-80 improved hydrolysis yields by up to 10 percent points.

Claims

1. A method for processing an aqueous stream of fines, comprising:

adding at least one surfactant to the aqueous stream of fines generated through a process of recycling old corrugated containerboards, and the aqueous stream comprises cellulosic fines which are rejected for recycling which have been separated from cellulosic fibers intended for recycling and papermaking fillers comprising calcium carbonate inorganic particles having an affinity for polysaccharide degradative enzymes, the at least one surfactant being added in an effective amount of between 3% to 10% by oven dry weight of the aqueous stream of fines, and the aqueous stream of fines lacks cellulose fibers suitable for papermaking;

adding at least one cellulose degrading enzyme to the aqueous stream of fines, in an amount sufficient to degrade at least a portion of the cellulosic fibers, to form an enzyme, surfactant, and fines-containing solution; and

maintaining the enzyme, surfactant, and fines-containing solution for a sufficient period of time to degrade at least a portion of the cellulosic fibers into fermentable sugars, to achieve at least 10% hydrolysis yield by weight of fermentable sugars per weight of biomass of the fines, having an increased hydrolytic yield with respect to a hydrolysis yield of fermentable sugars per weight of biomass of the fines for the amount of the at least one cellulose degrading enzyme for degrading cellulosic fibers in the aqueous stream of fines in an absence of the at least one surfactant.

2. The method according to claim 1, wherein the aqueous stream of fines is from an old corrugated cardboard recycling facility, and wherein the aqueous stream of fines has 3% lignin by oven dry weight of the aqueous stream of fines.

3. The method according to claim 1, wherein the effective amount of between 3% to 10% is effective to absorb to the calcium carbonate inorganic particles to reduce an affinity of the calcium carbonate inorganic particles for the at least one cellulose degrading enzyme, and below a level which causes agglutination of the aqueous stream of fines.

4. The method according to claim 1, wherein the calcium carbonate inorganic particles comprise precipitated calcium carbonate.

5. The method according to claim 1, wherein the papermaking fillers further comprise kaolin.

6. The method according to claim 1, wherein the at least one polysaccharide degradative enzyme comprises at least one of a cellulase and a hemicellulase.

7. The method according to claim 1, wherein the at least one surfactant comprises polysorbate.

8. The method according to claim 1, wherein the at least one surfactant comprises polysorbate 80.

9. The method according to claim 1, wherein the hydrolysis yield by weight of fermentable sugars per oven dry weight of the cellulosic fibers of the fines is at least 40%.

10. A method for enzymatically hydrolyzing a mixed aqueous stream, comprising:

receiving the mixed aqueous stream which is a waste product from recycling old corrugated containerboards into paper products, the mixed aqueous stream containing cellulosic fines selectively rejected for recycling into paper products separated from cellulosic fibers retained for recycling and papermaking fillers comprising calcium carbonate inorganic particles from the old corrugated containerboards having a binding affinity for hydrolytic enzymes, and the mixed aqueous stream lacks cellulosic fibers suitable for papermaking;

adding at least one surfactant to the mixed aqueous stream in an amount of between 3% and 10% by oven dry weight of the mixed aqueous stream;

adding at least one cellulose hydrolytic enzyme having a binding affinity for the calcium carbonate inorganic particles, and which are inhibited by binding to the calcium carbonate inorganic particles, to the mixed aqueous stream in an amount sufficient to degrade the cellulosic fines, wherein the at least one surfactant in the amount between 3% and 10% is effective to reduce the binding affinity of the at least one cellulose hydrolytic enzyme for the calcium carbonate inorganic particles; and

hydrolyzing the cellulosic fines with the added at least one cellulose hydrolytic enzyme, to achieve a hydrolytic yield of at least 10% sugars per gram oven dry weight of the cellulosic fines, wherein the hydrolytic yield is increased by the addition of the at least one surfactant in the amount of between 3% and 10% as compared to the hydrolytic yield absent addition of the at least one surfactant in the amount of between 3% and 10%.

11. The method according to claim 10, wherein the cellulosic fines comprise 3% lignin by weight of the oven dry weight of the mixed aqueous stream.

12. The method according to claim 10, wherein the amount between 3% and 10% is effective to absorb to the calcium carbonate inorganic particles to reduce an affinity of the calcium carbonate inorganic particles for the at least one cellulose hydrolytic enzyme, and below a level which causes agglutination of the mixed aqueous stream.

13. The method according to claim 10, wherein the calcium carbonate inorganic particles comprise precipitated calcium carbonate.

14. The method according to claim 13, wherein the papermaking fillers further comprise kaolin.

15. The method according to claim 10, wherein the at least one cellulose hydrolytic enzyme comprises at least one of a cellulase and a hemicellulase.

16. The method according to claim 10, wherein the at least one surfactant comprises polysorbate.

17. The method according to claim 10, wherein the at least one surfactant comprises polysorbate 80.

18. The method according to claim 10, wherein the hydrolytic yield by weight of fermentable sugars per oven dry weight of the cellulosic fines is at least 40%.

19. A method for enzymatically hydrolyzing a mixed stream of cellulosic fines and papermaking fillers comprising calcium carbonate-containing inorganic particles, comprising:

receiving the mixed stream of cellulosic fines which is a waste from a recycled paper mill which recycles paper to retain cellulose fibers for papermaking, and the mixed stream of cellulosic fines does not containing cellulose fibers suitable for papermaking, along with the papermaking fillers comprising calcium carbonate-containing inorganic particles from recycling of the paper;

adding at least one surfactant to the mixed stream, in an amount of between 3% and 10% by weight per an oven dry weight of the mixed stream;

adding at least one cellulose hydrolytic enzyme, having a binding affinity for the calcium carbonate-containing inorganic particles, and being competitively inhibited by binding to the calcium carbonate-containing inorganic particles, to the mixed stream;

the amount of the at least one surfactant being sufficient to reduce the binding affinity of the at least one cellulose hydrolytic enzyme for the inorganic particles and the competitive inhibition of the at least one cellulose hydrolytic enzyme by the calcium carbonate-containing inorganic particles, insufficient to inhibit the at least one cellulose hydrolytic enzyme, and insufficient to agglomerate the mixed stream;

adding an acidifier to the mixed stream; and

hydrolyzing the cellulosic fines with the at least one cellulose hydrolytic enzyme at a temperature of 40°

C. or higher,

wherein a hydrolytic yield of grams sugars per gram of cellulosic fines of at least 10% is achieved.

20. The method according to claim 19, wherein the at least one surfactant comprises polysorbate 80, the rejected cellulosic fines comprise 3% lignin by weight per an oven dry weight of the mixed stream, and the hydrolytic yield is at least 40%.