Self-sufficient process for the production of biomass hydrolysate with reduced salt content
The present invention is directed to a self-sufficient process for the production of biomass hydrolysate with reduced salt content as well as the de-salted hydrolysate produced after the inventive process and the use of the de-salted hydrolysate as a fermentation medium.
1. Process for the production of de-salted biomass hydrolysate comprising the steps
a) Providing a biomass;
b) Acidic pretreatment of the biomass;
c) Hydrolysis of the biomass to obtain a biomass hydrolysate;
d) Solid-liquid separation of the biomass hydrolysate to obtain a solid phase and a liquid phase;
e) Deionization of the liquid phase by electrodialysis using at least one bipolar membrane;
f) Separation of an acid and/or an alkaline fraction from the deionized liquid phase;
g) Addition of at least part of the separated acid fraction to step b)
wherein steps a) to g) are repeated at least once.
2. Process according to claim 1 , wherein the pretreatment is carried out by steam explosion.
3. Process according to claim 1 , wherein all of the separated acid fraction is added to step b).
4. Process according to claim 1 , wherein the hydrolysis of the biomass is carried out by enzymatic hydrolysis.
5. Process according to claim 4 , wherein at least part of the separated alkaline fraction is added to step c).
6. Process according to claim 5 , wherein the at least part of the separated alkaline fraction is added to step c) until the biomass has a pH in the range of from 4.5 to 5.5.
7. Process according to claim 1 , wherein the temperature of the biomass hydrolysate is set to a temperature selected from the range of from 50 to 95° C.
8. Process according to claim 1 , wherein at least part of the separated acid fraction is added to the biomass hydrolysate until the pH of the separated liquid phase is set to a pH selected from the range of from pH 1.5 to 4.5.
9. Process according to claim 1 , wherein the biomass is lignocellulose biomass.
10. Process according to claim 1 , wherein the electrodialysis using at least one bipolar membrane is followed by membrane capacitive deionization or ion exchange chromatography.