Abstract: Provided is a method for controlling the molecular weight (i.e., lowering) of microbially-derived celluloses. The lowering of the molecular weight is achieved by adding 2-deoxy-D-glucose to the liquid or solid medium in which Acetobacter xylinum or any other cellulose-producing microbe is grown. The molecular weight of the cellulose produced by the microbes grown in such media varies approximately inversely with the concentration of 2-deoxy-D-glucose in the culture medium. The method thus provided by the present invention is useful in providing microbial source cellulose which has a number average molecular weight of about 7.times.10.sup.5 to about 1.times.10.sup.4. Such lower molecular weight celluloses are useful in coatings formulations in which a relatively lower viscosity binder is desired.