Cutinase-Like Enzyme from the Yeast Cryptococcus sp. Strain S-2 Hydrolyzes Polylactic Acid and Other Biodegradable Plastics

ABSTRACT A purified lipase from the yeast Cryptococcus sp. strain S-2 exhibited remote homology to proteins belonging to the cutinase family rather than to lipases. This enzyme could effectively degrade the high-molecular-weight compound polylactic acid, as well as other biodegradable plastics, including polybutylene succinate, poly (ε-caprolactone), and poly(3-hydroxybutyrate).

Synthesis and Properties of Substituted Germylhydrazines

By using reactions between Me3GeBr or Me2GeCl2 and appropriate lithium hydrazide salts, the following new compounds were prepared: Me2NN(R)GeMe3 (R = H, 1; Me, 2; GeMe3, 3; SiMe3, 4), Me3GeN(Me)NHGeMe3, 5a, MeNHN(GeMe3)2, 5b, (Me3Ge)2NN(Me)GeMe3, 6, Me3GeNHNHGeMe3, 7a, (Me3Ge)2NNH2, 7b, (Me)11Ge4N6H, 11, (Me2GeNNMe2)3, 12, Me2Ge[N(R′)NMe2]2 (R′ = Me, 13; SiMe3, 14). Thus the reaction of Me3GeBr with Li(MeN2H2) and with LiN2H3 gave mixtures of disubstituted isomers, 5a and b, and 7a and b, respectively, rather than mono-substituted derivatives. Reactions of Me2GeCl2 gave (i) an unresolvable, highly condensed product with LiN2H3; (ii) the high molecular weight compound 11, with Li(MeN2H2); and (iii) the cyclic trigermazane 12 with Me2NNHLi; the extent of self-condensation is a function of the degree of substitution of the hydrazine moiety. Reactions with protic reagents (H2O, MeOH, anhydrous HCl) effect cleavage of the Ge—N bond in germylhydrazines. New compounds were characterized on the basis of i.r., n.m.r., and mass spectral measurements.

SOME FACTORS AFFECTING THE KÖNIGS–KNORR SYNTHESIS OF GLYCOSIDES

Glycosyl halides decompose readily in the presence of silver oxide under conditions generally used for the Königs–Knorr synthesis of glycosides. This "side reaction" probably accounts for the low yields commonly obtained in the synthesis of oligosaccharides, particularly those involving the formation of a glycosidic union through an unreactive secondary position. The rate of the side reaction, as well as that of the normal condensation reaction, is dependent on the condition of the silver oxide, and is retarded markedly by elemental iodine. This latter effect appears to be related to the improved yield obtained in Königs–Knorr syntheses when iodine is used. Among the products formed in the decomposition of 2,3,4,6-tetra-O-acetyl-α-D-mannopyranosyl bromide are 2,3,4,6-tetra-O-acetyl-D-mannose, a heptaacetyl 1,2,1′-linked dimeric orthoacetate, and a second high-molecular-weight compound that also shows ortho ester properties.