A detailed study and comparison was made on the catalytic activities of cutinases from Humilica insolens (HiC), Pseudomonas mendocina (PmC), Fusarium solani (FsC) using low-crystallinity (lc) biaxially oriented (bo) poly(ethylene terephthalate) (PET) films as model substrates. Cutinase activity for PET hydrolysis assayed a pH-stat to measure NaOH consumption versus time, where initial expressed units micromoles added per hour milliliter reaction volume. HiC found have good thermostability...

This paper describes the synthesis, crystal structure, and physicomechanical properties of a biobased polyester prepared from 2,5-furandicarboxylic acid (FDCA) 1,4-butanediol. Melt-polycondensation experiments were conducted by two-stage polymerization using titanium tetraisopropoxide (Ti[OiPr]4) as catalyst. Polymerization conditions (catalyst concentration, reaction time second stage temperature) varied to optimize poly(butylene-FDCA), PBF, molecular weight. A series PBFs with different Mw...

Omega-hydroxyfatty acids are excellent monomers for synthesizing a unique family of polyethylene-like biobased plastics. However, ω-hydroxyfatty difficult and expensive to prepare by traditional organic synthesis, precluding their use in commodity materials. Here we report the engineering strain diploid yeast Candida tropicalis produce commercially viable yields acids. To develop identified eliminated 16 genes encoding 6 cytochrome P450s, 4 fatty alcohol oxidases, dehydrogenases from C....

Candida antarctica Lipase B (CALB) was covalently immobilized onto epoxy-activated macroporous poly(methyl methacrylate) Amberzyme beads (235 µm particle size, 220 Å pore size) and nanoparticles (nanoPSG, diameter 68 nm) with a poly(glycidyl outer region. allowed CALB loading up to 0.16 g of enzyme per gram support. IR microspectroscopy generated images Amberzyme−CALB showed is localized within 50 thick front. images, recorded prior after treatment DMSO/aqueous Triton X-100, are similar,...

This Article describes the synthesis and physicomechanical properties of bioplastics prepared from methyl ω-hydroxytetradecanoic acid (Me-ω-OHC14), a new monomer available by fermentation process using an engineered Candida tropicalis strain. Melt-condensation experiments were conducted titanium tetraisopropoxide (Ti[OiPr]4) as catalyst in two-stage polymerization (2 h at 200 °C under N2, 4 220 0.1 mmHg). Poly(ω-hydroxytetradecanoate), P(ω-OHC14), Mw, determined SEC-MALLS, increased 53K to...

Biobased omega-carboxy fatty acid monomers 1,18-cis-9-octadecenedioic, 1,22-cis-9-docosenedioic, and 1,18-cis-9,10-epoxy-octadecanedioic acids were synthesized in high conversion yields from oleic, erucic epoxy stearic by whole-cell biotransformations catalyzed C. tropicalis ATCC20962. Maximum volumetric shake-flasks 17.3, 14.2, 19.1 g/L after 48 h for oleic 72 conversions acids, respectively. Studies fermentor with better control of pH glucose feeding revealed that to...

This study compares the synthesis and structure of poly(oleic diacid-co-glycerol) that results by using immobilized Candida antarctica Lipase B (Novozym 435, N435) dibutyl tin oxide (DBTO) as catalysts. By N435 catalysis an oleic diacid to glycerol molar ratio 1.0:1.0, resulting polyester number-average molecular weights (Mn) were 6000 g/mol at 6 h 9100 24 with low branching degree (Den% 13%−16%). 13C NMR spectra these polyesters revealed their chain-ends consist exclusively monosubstituted...

α-Chymotrypsin catalyzed oligomerization of the "dipeptide lego" KL-ethyl ester (OEt) in aqueous media triggers a rapid sol-gel transition due to formation alternating (KL)x. Resulting mixed chain oligomers, at alkaline pH, self-assemble into β-sheets. Thereafter, intermolecular backbone hydrogen bonding between peptides causes physically entangled nanofibrillar networks.

ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication the EditorNEXTA Cutinase with Polyester Synthesis ActivityMo Hunsen, Abul Azim, Harald Mang, Sabine R. Wallner, Asa Ronkvist, Wenchun Xie, and Richard A. GrossView Author Information NSF I/UCRC for Biocatalysis Bioprocessing of Macromolecules, Polytechnic University, Six Metrotech Center, Brooklyn, New York 11201 Cite this: Macromolecules 2007, 40, 2, 148–150Publication Date (Web):December 16, 2006Publication History...

This paper describes the protease-catalyzed synthesis of oligo(l-Lys) from l-Lys ethyl ester (l-Lys-Et) in an aqueous reaction medium at controlled pH using a pH-stat. Four proteases (papain, bromelain, α-chymotrypsin, and trypsin) were studied to determine their activity for oligomerization values ranging 6 11. Bromelain was found be preferred relative other protease catalysts because it gave highest yield optimal average chain length (DPavg). To evaluate progress product structure, 1H NMR...

High molecular weight (Mw > 25 000) poly(hexamethylene carbonate) (PHC) with polydispersity (Mw/Mn) ≤ 2.2 was successfully synthesized via copolymerization of diethyl carbonate 1,6-hexanediol catalyzed by immobilized Candida antarctica Lipase B (CALB). Because is highly volatile, polymerizations were performed a first stage oligomerization at low vacuum (600 mmHg pressure) followed second polymerization under high (1−5 pressure). Enzymatic polycarbonate synthesis preferably in solution...

IgG glycosylation differs in rheumatoid arthritis (RA) and osteoarthritis (OA), which should contribute to their pathogenesis research diagnosis.

ADVERTISEMENT RETURN TO ISSUECommunication to the...Communication the EditorNEXTGlycolipid Polymer Synthesized from Natural Lactonic Sophorolipids by Ring-Opening Metathesis PolymerizationWei Gao, Rena Hagver, Vishal Shah, Wenchun Xie, Richard A. Gross, M. Firat Ilker, Chrissy Bell, Kelly Burke, and E. Bryan CoughlinView Author Information NSF-I/UCRC Center for Biocatalysis Bioprocessing of Macromolecles, Department Chemical Biological Sciences, Polytechnic University, Six Metrotech Center,...

Four proteases (papain, bromelain, α-chymotrypsin and protease SG) were used to catalyze co-oligomerizations of l-leucine ethyl ester (l-Et-Leu) with diethyl-l-glutamate (l-(Et)2-Glu). Protease added reaction was normalized based on their relative activities for casein hydrolysis. With the exception papain that shows a very broad pH optimum oligo(γ-Et-l-Glu) synthesis, peptide synthesis above For l-(Et)2-Glu/l-Et-Leu (1:1 mol/mol) co-oligomerizations, order four is ≈ bromelain > SG. 1H NMR...

This paper explores reaction kinetics and mechanism for immobilized Humicola insolenscutinase (HIC), an important new biocatalyst that efficiently catalyzes non-natural polyester synthetic reactions. HIC, on Lewatit, was used as catalyst epsilon-caprolactone (CL) omega-pentadecalactone (PDL) ring-opening polymerizations (ROPs). Plots of percent CL conversion vs time were obtained in the temperature range from 50 to 90 degrees C. The kinetic plot ln([M]0/[M]t) (r2 = 0.99) HIC-catalyzed bulk...

Papain-catalyzed oligomerization of diethyl l-glutamate hydrochloride was conducted in phosphate buffer at 40 °C. Because rapid kinetics, high substrate concentrations were not needed to shift the equilibrium for oligomer synthesis. For example, 0.03 M hydrochloride, oligo(γ-ethyl l-glutamate) synthesis and precipitation from solution occurred 55% yield. MALDI-TOF spectra precipitated products showed two series ion peaks separated by 157 m/z units, mass oligo(γ-ethyl-l-glutamate) repeat...

This study explored Candida antarctica Lipase B (CALB)-catalyzed condensation reactions to prepare high-purity, metal-free, polycarbonate polyols. Terpolymerizations of diethyl carbonate (D) with 1,8-octanediol (O) and tris(hydroxymethyl)ethane (T) were performed in bulk at relatively low temperature (80 °C) using a pressure-varied two-stage process minimize evaporative loss carbonate. NMR experiments resulting polyols, including analysis proton resonances by COSY spectra carbon-13 HSQC,...

Controlled polymerization method to synthesize poly[methyl(3,3,3-trifluoropropyl)siloxane] with narrow molar mass distribution, broad “termination window”, selective end groups and quantitative transformation.

The direct oligomerization of l-lys-OMe by bromelain catalysis gave oligo(l-lys) with DPavg ∼ 3.6 and dispersity 1.1. Since higher chain length lower values one reactive amine for selective conjugation would be beneficial, we explored protease-catalyzed Nε-protected l-lys monomers where Nε-groups included tert-butoxycarbonyl (Boc) or benzyloxycarbonyl (Z) groups. By using monomers, oligopeptide side-chains are hydrophobic-neutral which should dramatically alter enzyme kinetic binding...

The intestinal microbiota closely interacts with the neuroendocrine system and exerts profound effects on host physiology. Here, we report that nucleotide-binding oligomerization domain 1 (Nod1) ligand derived from bacteria modulates catecholamine storage secretion in mouse adrenal chromaffin cells. cytosolic peptidoglycan receptor Nod1 is involved chromogranin A (Chga) retention dense core granules (DCGs) Mechanistically, upon recognizing its ligand, localizes to DCGs, recruits Rab2a, which...

ABSTRACT A series of random copolysiloxanes (PCDMS) containing various amount γ‐cyanopropyl groups are prepared by a new method under mild conditions. Structures the synthesized polymers fully characterized FTIR, 1 H NMR, 29 Si and GPC. Rheological properties PCDMS tested cone plate rheometer, thermal differential scanning calorimetry (DSC) thermogravimetry analysis (TGA). Damping as well fuel resistance cured elastomers also tested. The correlation between chemical structure, content...