Increasing Yields

From theEthanolSource.com

1 Overview
2 Using Other Feedstocks
- 2.1 Note
3 Increasing Yields with Glucanase
- 3.1 Use
4 Increasing Yields with Cellulase
- 4.1 Use
5 Increasing Yields with Xylanase
- 5.1 Use

Overview

Increasing yields in ethanol production has been one of the larger focuses of the U.S. Department of Energy's initiative. Researchers are working towards new enzymatic methods of converting corn and grain starch into more sugar, thus in turn, larger alcohol production. New yeasts are being genetically engineered to consome xylose, lactose and even cellulose.

Using Other Feedstocks

Corn stover, switchgrass and other feedstocks have been suggested as ethanol sources. All feedstocks need to be milled, shreaded and/or broken into as small of pieces as possible. Adjust pH to 4.8. Xylanase, glucanase and cellulase are added and let sit for several days. Sugar yield is checked with a saccharometer, then fermented.

Note

Yields may be considerable or nothing at all. Large amounts of research are aimed at making ethanol from other feedstocks.

Increasing Yields with Glucanase

Glucanase is the enzyme responsible for catalyzing the conversion of glucan to glucose. Glucose is directly usable by any fermenters yeast. Like xylan and cellulase, most grain contain at least a substantial portion of glucan. Glucanase can be added to the saccharification stage in the ethanol process. Depending on feedstock, yields can increase considerably.

Use

Dosage used is approximately equal to half the dosage of glucoamylase.

Increasing Yields with Cellulase

Cellulase is the enzyme responsible for the conversion of cellulose to glucose. Cellulose is a large portion of any plant. In fact, most plants are made out of entirely cellulose. Enzymatic conversion of cellulose is a key focus of study in ethanol fuel production. Using cellulase in the saccharification step can yield extra glucose for the yeast to consume. In turn, this allows for more alcohol production from the same amount of feed stock. In addition, cellulase helps thin the grain, freeing starches and other nutrients trapped by the cellular structure. Most cellulose is hidden deep within lignin of a plant. Lignins are a fibrous like material. To a plant, they are the tendons of their structure system. Most plants with a large portion of cellulose contain large amounts of lignin, as well. This lignin must be removed before the cellulose can be converted. Some plants produce lignin-free cellulose. Cotton and newspaper are two excellent sources of lignin-free cellulose. This cellulose can be directly converted to glucose.

Use

Dosage used is approximately equal to full dosage of glucoamylase.

Increasing Yields with Xylanase

Xylanase is the enzyme responsible for the conversion of xylan into xylose. Most plants contain some portion of xylan. With the use of both a xylose fermenting strain and the use of enzymatic conversion of xylan to xylose, yields from corn can be expected to raise up to 10%.

Use