Yasuteru Mawatari

Poly-3-hydroxybutyrate (PHB) production from alkylphenols, mono and poly-aromatic hydrocarbons using Bacillus sp. CYR1: A new strategy for wealth from waste

In the present study five different types of alkylphenols, each of the two different types of mono and poly-aromatic hydrocarbons were selected for degradation, and conversion into poly-3-hydroxybutyrate (PHB) using the Bacillus sp. CYR1. Strain CYR1 showed growth with various toxic organic compounds. Degradation pattern of all the organic compounds at 100 mg/l concentration with or without addition of tween-80 were analyzed using high pressure liquid chromatography (HPLC). Strain CYR1 showed good removal of compounds in the presence of tween-80 within 3 days, but it took 6 days without addition of tween-80. Strain CYR1 showed highest PHB production with phenol (51 ± 5%), naphthalene (42 ± 4%), 4-chlorophenol (32 ± 3%) and 4-nonylphenol (29 ± 3%). The functional groups, structure, and thermal properties of the produced PHB were analyzed. These results denoted that the strain Bacillus sp. CYR1 can be used for conversion of different toxic compounds persistent in wastewaters into useable biological polyesters.

Synthesis and solid state helix to helix rearrangement of poly(phenylacetylene) bearing n-octyl alkyl side chains

Highly stereoregular polymerisations of p-n-octyphenylacetylene (pOcPA) were performed using a [Rh(norbornadiene)Cl]2-triethylamine catalyst in ethanol at −20 and 25 °C to afford yellow and orange polymers, Poly(Y) and Poly(O), in yields of 64 and 99%, respectively. The XRD patterns of Poly(Y) showed a hexagonal columnar crystal with a contracted cis–cisoid helix, HexaPoly(Y)CC. The XRD pattern of Poly(O) matched that of Poly(Y) when heated to 80 °C. The heat treatment of HexaPoly(Y)CC at 100 °C generated two tetragonal crystals: Tetra1Poly(R)CC, containing contracted cis–cisoid helices, and Tetra2Poly(R)CT, containing stretched cis–transoid helices. The helical diameters of HexaPoly(Y)CC before and after heat treatment were estimated using XRD and were consistent with the results of MMFF 94 calculations, although the n-octyl alkyl chains of HexaPoly(Y)CC and Tetra2Poly(R)CT did not have linear alkyl chains; a bend in the chains was confirmed by 13C CP-MAS NMR. When HexaPoly(Y)CC was heated to 100 °C in the solid phase, the λmax in the diffuse reflective UV-vis spectra shifted from 448 nm to 565 nm. Furthermore, the endothermic transition for HexaPoly(Y)CC occurred at 100 °C in the DSC trace. Therefore, these data corroborated the assertion that HexaPoly(Y)CC thermally converted into Tetra1Poly(R)CC and Tetra2Poly(R)CT.

Helix oscillation of polyacetylene esters detected by dynamic 1H NMR, IR, and UV-vis methods in solution

An aliphatic substituted acetylene, n-heptyl propiolate, was stereoregularly polymerised using a catalyst, [Rh(nbd)Cl]2, at 40 °C in methanol to obtain the corresponding helical polymer, PnHepP. The changes in the line shapes and splitting patterns of the 1H NMR spectra were interpreted consistently as representing restricted rotation around the ester O–Ce bond in –O–CeHe2(R)– (R = n-hexyl alkyl chains), rather than helix inversion, with the aid of a 3-site jump model. A two-line peak corresponding to the ester methylene protons of –O–CH2– observed at 30 °C suggested the formation of three rotamers designated as A, B, and C based on the presence of contracted helix and stretched helix forms, each of which has an intrinsic helical pitch with a helical cis–cisoid structure. Furthermore, an accordion-like helix oscillation (HELIOS) along the main chain axis was proposed to explain the temperature dependence of spectral changes observed in the 1H NMR, UV-vis, and IR spectra. The temperature dependence of the UV-vis and 1H NMR spectra of PnHepP corroborated the presence of contracted and stretched one-handed helix sense polymers in solution.

Production of poly-3-hydroxybutyrate (P3HB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) P(3HB-co-3HV) from synthetic wastewater using Hydrogenophaga palleronii

In the present study, synthetic wastewater (SW) was used for production of poly-3-hydroxybutyrate (P3HB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) P(3HB-co-3HV) using the bacteria Hydrogenophaga palleronii. SW at various volatile fatty acids concentrations (5-60g/l) was evaluated for the growth and biopolymer production using H. palleronii. Substrate degradation was analyzed using total organic carbon (TOC) analyzer and high pressure liquid chromatography (HPLC). H. palleronii showed highest and lowest removal of TOC at 5g/l (88±4%) and 60g/l (15±6%) respectively. Among all the concentrations evaluated, bacteria showed highest biopolymer production with 20g/l (63±5%), followed by 30g/l (58±3%) and 40g/l (56±2%). Lowest biopolymer production was observed at 5g/l concentration (21±3%). Structure, molecular weight, and thermal properties of the produced biopolymer were analyzed. These results denoted that the strain H. palleronii can be used for degradation of high concentration of volatile fatty acids persistent in wastewaters and their subsequent conversion into useable biopolymers.

Mechanofluorochromism of 1-Alkanoylaminopyrenes

To create a new series of mechanofluorochromic materials and to elucidate the mechanism of the phenomenon of mechanofluorochromism, 1-alkanoylaminopyrenes including 1-acetylaminopyrene (AAPy), 1-octanoylaminopyrene (OAPy), and 1-stearoylaminopyren (SAPy) were prepared. It was found that these materials exhibited mechanofluorochromism with emission colors in the crystalline samples changing reversibly from bluish purple to yellowish green, which could be induced by mechanical grinding. X-ray crystal structure analysis, electronic absorption, and fluorescence spectroscopies, as well as fluorescence lifetime analysis and powder X-ray diffraction analysis of AAPy suggested that the present mechanofluorochromism was caused by developing crystal defects through grinding. Intermolecular hydrogen bonds were suggested to play an important role in the occurrence of mechanofluorochromism, suppressing the face-to-face overlapping of pyrene moieties to form excimers in the pristine crystal.

Polyhydroxyalkanoates (PHA) production from synthetic waste using Pseudomonas pseudoflava: PHA synthase enzyme activity analysis from P. pseudoflava and P. palleronii

Synthetic wastewater (SW) at various carbon concentrations (5-60g/l) were evaluated for polyhydroxyalkanoates (PHA) production using the bacteria Pseudomonas pseudoflava. Bacteria showed highest PHA production with 20g/l (57±5%), and highest carbon removal at 5g/l (74±6%) concentrations respectively. Structure, molecular weight, and thermal properties of the produced PHA were evaluated using various analytical techniques. Bacteria produced homo-polymer [poly-3-hydroxybutyrate (P3HB)] when only acetate was used as carbon source; and it produced co-polymer [poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) P(3HB-co-3HV)] by addition of co-substrate propionate. PHA synthase, the enzyme which produce PHA was extracted from two bacterial strains i.e., P. pseudoflava and P. palleronii and its molecular weight was analysed using SDS-PAGE. Protein concentration, and PHA synthase enzyme activity of P. pseudoflava and P. palleronii was carried out using spectrophotometer. Results denoted that P. pseudoflava can be used for degradation of organic carbon persistent in wastewaters and their subsequent conversion into PHA.

Degradation and conversion of toxic compounds into useful bioplastics by Cupriavidus sp. CY-1: relative expression of the PhaC gene under phenol and nitrogen stress

In this study different types of toxic compounds, i.e., alkylphenols, mono and poly-aromatic hydrocarbons were converted into polyhydroxybutyrate (PHB) using the isolated bacteria Cupriavidus sp. CY-1. The influence of Tween-80 on the toxic compound degradation ability of CY-1 was analyzed using high pressure liquid chromatography. Among all the compounds, CY-1 showed the highest removal of naphthalene (100 ± 6%), followed by phenol (96 ± 7%), and the lowest removal of alkylphenols without Tween-80 addition. However, Tween-80 addition enhanced the degradation capacity of CY-1, and showed the highest removal of 4-tertiary-butylphenol (74 ± 5%), followed by phenol (69 ± 5%), 4-chlorophenol (59 ± 3%), 4-tertiary-octylphenol (53 ± 5%), and naphthalene (48 ± 5%). Further experiments were carried out for conversion of toxic compounds into PHB. CY-1 grown with phenol (48 ± 6%) and naphthalene (42 ± 4%) showed the highest PHB production. The functional groups, structure and thermal properties of the produced PHB were analyzed. In addition the expression of the PhaC gene was quantified at the transcriptional level through real time quantitative PCR. The results showed up-regulation of the PhaC gene in the presence of phenol, and up and down-regulations in the presence of nitrogen. The maximum PhaC transcript expression was 5.37 folds at 100 mg l−1 nitrogen concentration.

Emerging π-Conjugated Stretched and Contracted Helices and their Mutual Conversions of Substituted Polyacetylenes Prepared using an Organo-rhodium Catalyst

ABSTRACT Interconvertible stretched and contracted helices of mono-substituted polyacetylenes (SPA)s prepared using a [Rh(norbornadiene)Cl]2-amine or alcohol catalyst are demonstrated along with the reason for why the Rh catalytic system was used. The interconversions between their helices with color changes in the solid state were controlled by choosing the polymerization solvents, substituents, and/or external stimuli. The accordion-like helix oscillation, HELIOS, of the aliphatic polyacetylene ester main chain was found in a solution where restricted rotations around the O‒C bond in the ester side-chain are dynamically synchronized. The magnetic behavior of the cis and trans radicals of SPAs produced through the rotational scission of the cis C=C bonds is also reported.

Configuration and conformation of poly(3-carbazolylacetylene) including cis and trans radicals revealed by ESR spectroscopy

π-Conjugated cis and trans radicals of poly(N-isobutyl-3-carbazolylacetylene), P(iBCzA), were stereospecifically prepared using the [Rh(norbornadiene)Cl]2-triethylamine catalyst in toluene as the polymerization solvent at room temperature, and their geometric structures were determined using the electron spin resonance (ESR) method. The deuterated analogue, P(iBCzA-d1), with vinyl protons replaced with deuterium, D–C, was used to corroborate the structures together with the simulation of the observed ESR spectra and the calculation of the spin densities of the two radicals. The cis and trans radicals were generated at 1 : 1 ratio with spin densities delocalized on the main chain rather than the side-chain, unlike other substituted polyacetylenes, which have relatively small side-chains. This finding indicates that the large and planar carbazole moieties of the two radicals were perpendicular to the π-conjugated main-chain and that fairly stiff π-conjugated main chains were generated.

Synthetic Molecular Springs: Stretched and Contracted Helices with Their Interconversions of Monosubstituted Polyacetylenes Prepared with a Rhodium Complex Catalyst

Stereoregular monosubstituted polyacetylenes (SPAs) can be prepared by polymerizing the corresponding monosubstituted acetylene monomers using a bidentate rhodium–diene complex with either an amine or alcohol cocatalyst. SPAs have advantages over polyacetylene (PA) in terms of handling and application because SPAs are stable in air and soluble in organic solvents, whereas PA is unstable in air and insoluble. The main chains of SPAs form unique helical structures because of the steric hindrance between neighboring monomers. SPAs can be switched between stretched and contracted helices by controlling the polymerization solvents, substituents, and temperature, leading to color changes in the solid-state materials. An “accordion-like helix oscillation” (HELIOS) was observed in a solution of a SPA with aliphatic ester groups, where the restricted rotation of the ester O–C bond was dynamically synchronized with changes in the helical pitch of the SPA molecules.