Introduction         We are interested in biotechnological routes to cellulose derivatives for several reasons.  First, there is an inherent interest in developing "green" methods for producing existing commercial products, such as cellulose derivatives.  Secondly, we are interested in topochemical reactions, i.e. reactions which affect the surface but not the interior of cellulose or other bio-nanoparticles.  Thirdly, enzymatic reactions tend to preserve chiral centers and often exhibit regio-selectivity far beyond what is readily achievable by by classical, wet methods.  In this work we report the isolation, characterization and esterification characteristics of an intracellular carbohydrate carboxylesterase (EC 3.1.1.1) derived from the soil bacterium Arthrobacter viscosus NRRL B-1973.