Integrated Feedstock Supply Systems for Corn Stover Biomass

Introduction

This project addresses critical needs for corn stover feedstock development through an integrated multidisciplinary approach. The collaboration includes Iowa State University, the University of Wisconsin-Madison, the USDA Dairy Forage Research Center, the USDA Corn Insect and Crop Genetics Research Unit, and the World Resources Institute, with industry partners John Deere and Genencor International. Research teams are focused on plant breeding and crop physiology, harvest and storage technologies, and systems evaluation and integration. The overall goal is to develop productive, efficient, and sustainable strategies for corn stover biomass as a primary feedstock for the bioeconomy of the 21^st century, while significantly improving the rural agro-industrial economy.

Corn stover is widely recognized as the most promising high volume, low cost lignocellulosic feedstock on which to base a range of biobased energy, chemical, and material industries for the next several decades. However, several significant challenges must be addressed before this vision can be achieved.  First, stover biomass must be supplied at a price that is competitive with petroleum, profitable for producers, and grows the rural agroindustrial economy.  To achieve these economic objectives new technologies must be developed and optimized for stover harvest and storage. As stover becomes a significant feedstock commodity, the genetic potential of corn must be exploited to increase both stover yield and biomass conversion rates. And as these new technologies and varieties are developed and optimized, they must be implemented in ways that are sustainable with respect to soil, the environment, and rural communities. 

Objectives

This project will address these challenges to develop next-generation integrated systems for corn stover feedstock supply. The overall objectives of this project are to:

• develop innovative harvesting and storage technologies to efficiently and economically move corn stover from the field to the factory gate with physical and chemical properties optimal for the conversion processes

• identify genetic varieties of corn with specific properties attractive for biobased industries and initiate a breeding program to enhance those properties; and

• evaluate and optimize these systems for efficiency, and economic and environmental sustainability.

For harvest and storage, the primary emphasis will be on developing innovative single-pass harvesting and wet storage systems, which have both economic and technical advantages for centralized bioconversion processes. Conventional multi-pass and dry storage systems will be included for comparative purposes, and for their potential in decentralized and thermochemical conversions such as gasification.  Specific corn breeding targets include lignin and cellulose metabolism for their impacts on fiber quality and hydrolysis characteristics; silica content for its impact on downstream bioprocessing and thermochemical conversion; and yield and distribution of corn biomass among stover constituents with respect to densification and conversion characteristics. System integration goals include increased overall biomass productivity, efficient use of nutrients and energy; improved soil quality; and enhanced rural economic development.