Chapter 25 - Value-Added Products from Animal Manure

Abstract

This chapter reviews several examples of utilizing animal manure as feedstock for producing value-added products. It characterizes three types of animal manure, cattle, poultry, and swine manure by their fiber, protein/amino acid, and elements content. It also examines the conversion of cattle manure fiber into fermentable reducing sugars by acid and enzymatic hydrolysis. Finally, a fungal-culture process for producing cellulase enzymes from dairy manure is presented. These results, however, are limited to laboratory studies. The utilization of animal manure for value-added products provides a potential alternative to traditional animal manure management practices, yielding saleable bioproducts while alleviating environmental concerns. Lignocellulosics are a major component of animal manure, especially cattle manure, and are capable of being hydrolyzed into reducing sugars, which can be further converted into various value-added products by biological or chemical processes. Utilizing cattle manure lignocellulosics to produce fermentable reducing sugars is still not economical. Acid-hydrolysis, especially with concentrated acid decrystallization, results in a very high sugar yield, but causes even more environmental concerns than manure disposal. Producing cellulase from dairy manure is a promising way to reduce the high cellulase cost and provides a new way for utilizing not only manure fiber, but also nitrogen, phosphorus, and other nutrients.