The Academy Lecture

Rajai H. Atalla

The Species Specificity of the Structures of Native Celluloses

Our understanding of the diversity of native celluloses has been limited because studies of their structures have focused on the search for ideal crystal lattice forms for the native state. Departures from ideal structures have been viewed as defects in an ideal lattice. Native celluloses, in contrast, consist of a naturally occurring well-organized biological polymer, the biogenesis of which involves a high degree of orchestration of the processes of primary structure development and the patterns of aggregation of the molecular chains in a manner that is genetically encoded and species specific. Recent studies have shown that all celluloses that are relatively pure in their native states are composites of two distinct forms that are intimately blended during biogenesis in a manner and in proportions that are unique to the species producing them and sometimes to the environmental conditions under which biogenesis occurs. Thus there is a need for new conceptual frameworks for the description of native celluloses. The uniqueness of particular native structures appears to emerge at the nanoscale level, which is not well detected or characterized by traditional methods for the investigation of structure. This report will describe efforts to characterize the nature of native celluloses and their states of aggregation and explore the possibility of correlations of their diversity with the diversity of cellulose synthase enzyme systems that have been identified in different plants. Success in such an effort may allow more comprehensive systematization of the wide variety of native structures.

The Lecturer

Rajai Atalla has a PhD in Chemical Engineering (minor in Molecular Physics) from the University of Delaware. Prior to his current position, he was Head, Chemistry and Pulping Research (1989-98); Associate Professor and Professor (1968-89) at the Institute of Paper Chemistry, Appleton, WI; and Research Engineer, Hercules Research Center, Hercules Inc, Wilmington, DE (1960-68). Among his awards are Anselme Payen Award of the Cellulose Division of the American Chemical Society (1998), Forest Service Chief's Distinguished Scientist Award (1996), USDA Secretary's Honor Award for Personal and Professional Excellence (1995), selected 1995 Forest Service Engineer of the Year-Technical, elected Fellow of TAPPI (1993), elected Fellow of the International Academy of Wood Science (1992), and selected among Outstanding Educators (1972).

Presented at the 56th Annual Meeting of the Forest Products Society at Madison, Wisconsin, 26 June 2002.