Methods for fermenting carbohydrate-rich crops

摘要

A method for fermenting carbohydrate-rich crops is provided. Sugar beet, sugar cane, sweet sorghum, tropical maize hybrids and fruits are rich in simple sugars; potato, sweet potato, cassava and yam are rich in starch; and Jerusalem artichoke is rich in inulin. This method uses vacuum infusion to infuse yeast into the intercellular space (apoplast) of the parenchyma tissue. The simple sugars diffuse into the apoplast, come into contact with the yeast and produce ethanol. Ethanol can be extracted from the crop by vacuum stripping or crushing or can be left inside the starchy crop to preserve it. In some variants, pectinase enzymes degrade the parenchyma cell walls to speed up diffusion of simple sugars to the yeast, speed up diffusion of amylase to starch granules or speed up diffusion of inulinase to insoluble inulin.

主权项

1. A process for producing fermentation products from carbohydrate-rich plant parenchyma tissue, said process comprising the steps of:
(a) providing carbohydrate-rich plant parenchyma tissue containing an apoplast at a crop temperature; (b) combining said carbohydrate-rich plant parenchyma tissue with an aqueous reagent solution containing a yeast, at a reagent temperature; (c) exposing said carbohydrate-rich plant parenchyma tissue to a gas-phase preparation pressure for a preparation time, either prior to step (b) or following step (b), wherein said gas-phase preparation pressure is less than atmospheric pressure; (d) exposing said carbohydrate-rich plant parenchyma tissue to a gas-phase infusion pressure for an infusion time, wherein said yeast infuses into said apoplast, and wherein said gas-phase infusion pressure is greater than said gas-phase preparation pressure; (e) draining free liquid that has not been drawn into said apoplast; and (f) after step (e), maintaining a gas-phase fermentation pressure for a fermentation time to produce fermentation products within said apoplast without reintroducing said aqueous reagent solution back to said carbohydrate-rich plant parenchyma tissue, wherein said gas-phase fermentation pressure is greater than said gas-phase preparation pressure, wherein said fermentation products are produced by fermentation of carbohydrates selected from the group consisting of simple sugars, simple sugars hydrolyzed from starch, simple sugars hydrolyzed from inulin, and combinations thereof, wherein at least 25% of the mass of said fermentation products is ethanol, and wherein at least 25% of the mass of said fermentation products is carbon dioxide, and wherein said carbon dioxide does not expel said yeast from said apoplast during said fermentation.