BIODEGRADATION OF CELLULOSE-ACETATE BY NEISSERIA-SICCA

Bacteria capable of assimilating cellulose acetate, strains SE and SC, were isolated from soil on a medium containing cellulose acetate as a carbon source, and identified as Neisseria sicca, Both strains degrad ed cellulose acetate membrane filters (degree of substitution, DS, mix ture of 2.8 and 2.0) and textiles (DS, 2.34) in a medium containing ce llulose acetate (DS, 2.34) or its oligomer, but were not able to degra de these materials in a medium containing cellobiose octaacetate. Biod egradation of cellulose acetate (DS, 1.81 and 2.34) on the basis of bi ochemical oxygen demand reached 51 and 40% in the culture of N. sicca SE and 60 and 45% in the culture of N. sicca SC within 20 days. A decr ease in the acetyl content of degraded cellulose acetate films and pow der was confirmed by infrared and nuclear magnetic resonance analyses, After 10-day cultivation of N. sicca SB and SC, the number-average mo lecular weight of residual cellulose acetate decreased by 9 and 5%, re spectively. Activities of enzymes that released acetic acid and produc ed reducing sugars from cellulose acetate were mainly present in the c ulture supernatant. Reactivity of enzymes for cellulose acetate (DS, 1 .81) was higher than that for cellulose acetate (DS, 2.34).