ABSTRACT
The microbial degradation behavior of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) and its compound with several polyesters such as poly(butylene adipate-co-telephtharate) (PBAT), poly(butylene succinate) (PBS), and polylactic acid (PLA) in seawater was tested by a biological oxygen demand (BOD) method. PHBHHx showed excellent biodegradation in seawater in this study. In addition, the biodegradation rate of several blends was much influenced by the weight ratio of PHBHHx in their blends and decreased in accordance with the decrement of PHBHHX ratio. The surface morphology of the sheet was important factor for controlling the biodegradation rate of PHBHHx-containing blends in seawater.
Subject(s)
3-Hydroxybutyric Acid/chemistry , Caproates/chemistry , Polyesters/chemistry , Seawater/chemistry , Biocompatible Materials/chemistry , Materials Testing/methods , Surface PropertiesABSTRACT
A Michael reaction of chitosan was conducted in water containing acetic acid with various acryl reagents. The degree of substitution could be controlled by temperature, reaction time, and the amount of acryl reagents. Although the modified chitosan derivatives with acrylic acid esters showed water-solubility, that with poly(ethylene glycol) acrylate, however, turned to water-insoluble material by lyophilization. Good biodegradation was observed in modified chitosan derivatives by standard activated sludge.
Subject(s)
Biocompatible Materials/chemistry , Chitin/analogs & derivatives , Chitin/chemistry , Acylation , Biocompatible Materials/metabolism , Biodegradation, Environmental , Chitin/metabolism , Chitosan , Magnetic Resonance Imaging , Sewage , Solubility , WaterABSTRACT
Chitosan-dendrimer hybrids having various functional groups such as carboxyl, ester, and poly(ethylene glycol) groups were prepared successfully using dendrimer acetal by reductive N-alkylation. The synthetic procedure could be accomplished by one-step reaction without organic solvent. The degree of substitution of dendrimer was 0.13-0.18 evaluated by (1)H NMR. A perfectly or partially water-soluble chitosan-dendrimer hybrid could be obtained. By standard activated sludge, good biodegradation was observed in these hybrids.
Subject(s)
Biocompatible Materials/chemical synthesis , Chitin/analogs & derivatives , Chitin/chemical synthesis , Alkylation , Biocompatible Materials/metabolism , Biodegradation, Environmental , Chitin/metabolism , Chitosan , Magnetic Resonance SpectroscopyABSTRACT
The Michael type reaction of chitosan with ethyl acrylate has been investigated. Although this reaction was quite slow in the case of chitosan, the reiteration of the reaction was an effective means for increasing the degree of substitution (DS) of ethyl ester. The N-carboxyethylchitosan ethyl ester as an intermediate was successfully substituted with various hydrophilic amines, although the simultaneous hydrolysis of the ester to carboxylic acid also occurred. Water-soluble chitosan derivatives were obtained by substitution with hydroxyalkylamines and diamines.
Subject(s)
Chitin/analogs & derivatives , Chitin/chemistry , Chitin/chemical synthesis , Esters/chemical synthesis , Acrylates/chemistry , Amines/chemistry , Chitosan , Esters/chemistry , Solubility , Water/chemistryABSTRACT
The selective and efficient production of N-acetyl-D-glucosamine (GlcNAc) was achieved from flake type of alpha-chitin by using crude enzymes derived from Aeromonas hydrophila H-2330.
Subject(s)
Acetylglucosamine/metabolism , Aeromonas hydrophila/enzymology , Chitin/metabolism , Animals , Brachyura/chemistry , Chitinases/metabolism , Chromatography, High Pressure LiquidABSTRACT
Commercial non-chitinase enzymes from Aspergilus niger, Acremonium cellulolyticus and Trichoderma viride were investigated for potential utilization in the preparation of 2-acetamido-2-deoxy-D-glucose (N-acetyl-D-glucosamine, GlcNAc) from chitin. Among the tested enzymes, cellulase A. cellulolyticus exhibited highest chitinolytic activity per weight toward amorphous chitin and beta-chitin from squid pen. The optimum pH of the enzyme was 3 where it produced two major hydrolytic products, GlcNAc and N,N'-diacetylchitobiose ([GlcNAc](2)). The product ratio, GlcNAc:[GlcNAc](2), increased while the total yield decreased as the pH was raised from 3. All of the [GlcNAc](2) produced at pH 3 can be converted in situ to GlcNAc by mixing cellulase A. cellulolyticus with one of several other enzymes from A. niger resulting in a higher yield of GlcNAc. An appropriate mixing ratio of cellulase A. cellulolyticus to another enzyme was 9:1 (w/w) and an optimum substrate concentration was 20 mg/mL.
