Enzymatic hydrolysis of biomasses having a high dry matter (DM) content
The present invention relates to a process for liquefaction and saccharification of polysaccharide containing biomasses, having a relatively high dry matter content. The present invention combines enzymatic hydrolysis with a type of mixing relying on the principle of gravity ensuring that the biomasses are subjected to mechanical forces, primarily shear and tear forces. Furthermore, the present invention relates to the further utilization of such processed biomasses, e.g. for subsequent fermentation into bio-ethanol, bio-gas, specialty carbohydrates for food and fees as well as carbon feedstock for processing into plastics and chemicals.
1. A process for liquefaction of polysaccharide containing biomasses comprising subjecting a polysaccharide containing biomass having a final dry matter content of between 20% and 40% and comprising lignocellulosic biomass to:
a) enzymatic hydrolysis using at least one cellulase enzyme, and
b) mixing by a free fall type mixing that provides mechanical degradation of the biomass during hydrolysis,
wherein the biomass is changed to a more or less viscous liquid prior to further processing and
wherein said further processing optionally includes fermentation.
2. A process for liquefaction of polysaccharide containing biomasses comprising subjecting a polysaccharide containing biomass having a final dry matter content of between 20% and 40% and comprising primarily lignocellulosic biomass to:
a) enzymatic hydrolysis using at least one cellulase enzyme, and
b) mixing by a free fall type mixing that provides mechanical degradation of the biomass during hydrolysis,
wherein the biomass is changed to a more or less viscous liquid prior to further processing and
wherein said further processing optionally includes fermentation.
3. A process according to claim 2 wherein the lignocellulosic biomass has a distribution of particle sizes in which at least 20% (w/w) are between 26-70 mm in size before pre-treatment.
4. A process according to claim 1 , wherein the polysaccharide containing biomass comprising lignocellulosic biomass is further characterized by comprising primarily a mixture of starch containing grains or refined starch and lignocellulosic biomasses derived from agricultural crops.
5. A process according to any one of claims 1 - 2 , wherein the polysaccharide containing biomass comprises primarily lignocellulosic biomass derived from corn stover, bagasse, rice straw, wheat straw, rye straw, oat straw, barley straw, rye straw, rape straw, sorghum straw, softwood, hardwood, municipal solid waste, or waste paper.
6. A process according to any one of claims 1 - 2 , wherein the polysaccharide containing biomass comprises lignocellulosic biomass that has been subjected to heat pre-treatment between 110-250° C.
7. A process according to any one of claims 1 - 2 , carried out as a batch, continuous, fed-batch, or other semi-continuous process.
8. A process according to any one of claims 1 - 2 wherein additional mechanical degradation of the biomass is provided by steel balls or similar material that collides with the biomass during mixing.
9. A process according to any one of claims 1 - 2 wherein the biomass is changed to a more or less viscous liquid prior to further processing within 3 to 24 hours.
10. A process according to any one of claims 1 - 2 wherein the polysaccharide containing biomass comprises primarily lignocellulosic biomass that has been subjected to heat pretreatment between 160-200° C.
11. A process according to any one of claims 1 - 2 wherein the polysaccharide containing biomass comprises primarily lignocellulosic biomass that has been subjected to heat pretreatment for 1-60 min.
12. A process according to any one of claims 1 - 2 wherein the polysaccharide containing biomass comprises primarily lignocellulosic biomass that has been subjected to heat pretreatment for 5-30 min.
13. A process according to any one of claims 1 - 2 wherein mixing is accomplished in a drum mixer.
14. A process according to any one of claims 1 - 2 wherein mixing is accomplished in a drum mixer having rotation with periodically alternated rotating direction.
15. A process according to any one of claims 1 - 2 wherein mixing is accomplished in a drum mixer having rotation with pre-defined intervals.
16. A process according to any one of claims 1 - 2 wherein mixing is accomplished in a mixer with a horizontally placed stirrer shaft lifting the biomass.
17. A process according to any one of claims 1 - 2 wherein mixing is accomplished in a mixer with a horizontally placed stirrer shaft lifting the biomass and having rotation with periodically alternated rotating direction.
18. A process according to any one of claims 1 - 2 wherein mixing is accomplished in a mixer with a horizontally placed stirrer shaft lifting the biomass and having rotation with pre-defined intervals.
19. A process according to claim 2 wherein the distribution of fibre and particle sizes of lignocellulosic biomass is between 0-150 mm.
20. A process according to claim 2 wherein the degree of enzymatic hydrolysis of lignocellulosic biomass is between 30-50%.
21. A process according to any one of claims 1 - 2 wherein the further processing comprises gasification, hygrogenation, organic synthesis, or production of biogas or feed.