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1.
Thermophilic actinomycetes strains were isolated from various environment in Taiwan and screened for degradation of poly(ethylene
succinate) (PES), poly(ε-caprolactone) (PCL) and/or poly(β-hydroxybutyrate) (PHB) by the clear-zone method. Out of 341 strains
of thermophilic actinomycetes, 105 isolates were PHB-degraders (30.8%), 198 isolates were PCL-decomposers (58.1%), and 99
isolates could degrade PES (29.0%). Furthermore, 77 isolates could degrade both PHB and PCL (22.6%), 35 isolates could degrade
both PHB and PES (10.3%), 81 isolates could degrade both PES and PCL (23.8%) and 31 isolates could degrade the three polyesters
used in this study (9.1%). Base on the morphological and chemical characteristics, these 31 isolates belonging to Actinomadura (12.9%), Microbispora (25.8%), Streptomyces (48.4%), Thermoactinomyces (9.7%) and Saccharomonospora genus (3.22%). 相似文献
2.
Thermophilic actinomycetes were isolated from sediment of the Chingshuei hot spring in north Taiwan, and the strain HS 45-1
was selected from colonies which formed distinct clear zones on agar plate with emulsified polyethylene succinate (PES). The
film of PES disappeared within 6 days in liquid cultures at 50°C. The strain HS 45-1 was also able to degrade poly (ε-carpolactone)
(PCL) and poly (3-hydroxybutyrate) (PHB) films completely within 6 days in liquid cultures. Basing on the results of phynotypic
characteristics, phylogenetic studies and DNA-DNA hybridization, strain HS 45-1 should be assigned to Micorbispora rosea subsp. taiwanensis. 相似文献
3.
Often, degradability under anaerobic conditions is desirable for plastics claimed to be biodegradable, e.g. in anaerobic biowaste treatment plants, landfills and in natural anaerobic sediments. The biodegradation of the natural polyesters poly(beta-hydroxybutyrate) (PHB), poly(beta-hydroxybutyrate-co-11.6%-beta-hydroxyvalerate) (PHBV) and the synthetic polyester poly(epsilon-caprolactone) (PCL) was studied in two anaerobic sludges and individual polyester degrading anaerobic strains were isolated, characterized and used for degradation experiments under controlled laboratory conditions. Incubation of PHB and PHBV films in two anaerobic sludges exhibited significant degradation in a time scale of 6-10 weeks monitored by weight loss and biogas formation. In contrast to aerobic conditions, PHB was degraded anaerobically more rapidly than the copolyester PHBV, when tested with either mixed cultures or a single strained isolate. PCL tends to degrade slower than the natural polyesters PHB and PHBV. Four PHB and PCL degrading isolates were taxonomically identified and are obviously new species belonging to the genus Clostridium group I. The depolymerizing enzyme systems of PHB and PCL degrading isolates are supposed to be different. Using one isolated strain in an optimized laboratory degradation test with PHB powder, the degradation time was drastically reduced compared to the degradation in sludges (2 days vs. 6-10 weeks). 相似文献
4.
Hydrolysis of polyesters by serine proteases 总被引:2,自引:0,他引:2
The substrate specificity of -chymotrypsin and other serine proteases, trypsin, elastase, proteinase K and subtilisin, towards hydrolysis of various polyesters was examined using poly(L-lactide) (PLA), poly(-hydroxybutyrate) (PHB), poly(ethylene succinate) (PES), poly(ethylene adipate) (PEA), poly(butylene succinate) (PBS), poly(butylene succinate-co-adipate) (PBS/A), poly[oligo(tetramethylene succinate)-co-(tetramethylane carbonate)] (PBS/C), and poly(-caprolactone) (PCL). -Chymotrypsin could degrade PLA and PEA with a lower activity on PBS/A. Proteinase K and subtilisin degraded almost all substrates other than PHB. Trypsin and elastase had similar substrate specificities to -chymotrypsin. 相似文献
5.
Commercial lipases were examined for their degradation efficiency of aliphatic polyester films. In 100 days immersion of polyester films in lipase solutions at37 °C at pH 7.0,Lipase Asahi derived from Chromobacterium viscosum degraded polybutylene succinate-co-adipate (PBSA), poly (-caprolactone) (PCL) and polybutylene succinate (PBS), and Lipase F derived from Rhizopus niveus degraded PBSA and PCL during 4–17 days. Lipase F-AP15 derived fromRhizopus orizae could degrade PBSA in 22 days. In these cases, PBS and PBSA were mainly degraded to dimers, whereas PCL was mainly degraded to monomers. Only poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHB/V) and poly (L-lactide) (PLA) were not degraded in the experiments. However, PLA degraded completely at 55 °C, pH 8.5 with Lipase PL during 20 days. This result could be explained with the sequential reactions of the chemical hydrolysis of the polymer to oligomers at higher pH and temperature, and the succeeding enzymatic hydrolysis of oligomers to the monomers. 相似文献
6.
Thirty mesophilic and thermophilic bacteria were isolated from thermobiotically digested sewage sludge in culture medium supplemented with poly-ε-caprolactone (PCL). The ability of each purified isolate to degrade PCL and to produce polymer-degrading extracellular enzymes was assessed. Isolates were characterized based on random amplified polymorphic DNA (RAPD), 16S rDNA sequence-based phylogenetic affiliation and carbohydrate-based nutritional versatility. Mesophilic isolates with ability to degrade PCL were attributed to the genera Acinetobacter, Burkholderia, Pseudomonas, and Staphylococcus. Thermophilic isolates were members of the genus Bacillus. Despite the restricted phylogenetic and genotypic diversity observed for thermophiles, their metabolic versatility and wide range of growth temperatures suggest an important activity of these organisms during the whole composting process. 相似文献
7.
This paper examined the biodegradability of a new aliphatic polyester, polyethylene succinate (PES), at a high incubation temperature of 50°C. The distribution and population of total colonies and of PES degrading micro organisms on polymer-emulsified agar plates were determined using the plate count and clear zone methods. The PES-decomposers were present in six of 10 soil samples and the total number ranged from 2.0×104 to 2.2×106 c.f.u./g of samples. Degrading microorganisms constituted between 20 and 80% of the total colonies on PES–agar plates. A single PES-degrading strain, TT96, was isolated and tested for its biodegrading capacity on PES powder and on other aliphatic polyesters: poly(beta-hydroxybutyrate) (PHB), polycaprolactone (PCL), poly(butylene succinate) (PBS), and poly(L-lactide) (PLA). Degraded films of PES and PBS were presented and compared using scanning electron microscopy. Strain TT96 was able to create clear zones on all the polymers used, except on PHB-agar plates. Liquid culture test after 2 weeks showed that TT96 completely degraded PCL powder but had very little activity on other samples. Scanning electron micrograph confirmed the microbial attack of TT96 on PES and PBS films. PES film surfaces were degraded more uniformly compared to PBS films which were decomposed only in some parts. 相似文献
8.
Ci Su-Qin Chen Shan Dong-Bo Liu Hong-Mei Xia 《World journal of microbiology & biotechnology》2006,22(7):729-735
Summary
Penicillium sp. DS9713a-01 was obtained by ultraviolet (u.v.) light mutagenesis from the Penicillium sp. DS9713a which can degrade poly (3-hydroxybutyrate) (PHB). The enzymatic activity of DS9713a-01 was 97% higher than that
of the wild-type strain. The DS9713a-01 mutant could completely degrade PHB films in 5 days; however, the wild-type strain
achieved only 61% at the same time. The extracellular PHB depolymerase was purified from the culture medium containing PHB
as the sole carbon source by filtration, ammonium sulfate precipitation and chromatography on Sepharose CL-6B. The molecular
weight of the PHB depolymerase was about 15.1kDa determined by SDS-polyacrylamide gel electrophoresis. The optimum activity
of the PHB depolymerase was observed at pH 8.6 and 50 °C. The enzyme was stable at temperatures below 37 °C and in the pH
range from 8.0 to 9.2. The activity of PHB depolymerase could be activated or inhibited by some metal ions. The apparent K
m
value was 0.164 mg ml−1. Mass spectrometric analysis of the water-soluble products after enzymatic degradation revealed that the primary product
was the monomer, 3-hydroxybutyric acid. 相似文献
9.
Polymer production by two newly isolated extremely halophilic archaea: application of a novel corrosion-resistant bioreactor 总被引:3,自引:0,他引:3
Hezayen FF Rehm BH Eberhardt R Steinbüchel A 《Applied microbiology and biotechnology》2000,54(3):319-325
A novel corrosion-resistant bioreactor composed of polyetherether ketone (PEEK), tech glass and silicium nitrite ceramics
was constructed and applied for the cultivation of two newly isolated, extremely halophilic archaea producing poly(γ-glutamic
acid) (PGA), or poly(β-hydroxy butyric acid) (PHB), respectively. These bacteria were isolated from hypersaline soil close
to Aswan (Egypt). The isolate strain 40, which is related to the genus Natrialba, produced large amounts of PGA when cultivated on solid medium. Culture conditions were optimised applying the corrosion-resistant
bioreactor. PGA production was dependent on NaCl concentration and occurred about at 20% (w/v) NaCl in the medium. A maximum
cell density of about 1.6 g cell dry matter/l was obtained when the bioreactor was stirred and aerated in a batch fermentation
process using proteose-peptone medium. The supernatant was monitored with respect to PGA formation, and after 90 h a maximum
of 470 mg/l culture volume was detected by HPLC analysis. Culture conditions were optimized for the isolate 56, which accumulated
PHB as intracellular granules. Batch fermentations in the stirred and aerated bioreactor applying acetate and n-butyric acid as carbon sources led to cell density of 2.28 g cell dry matter/l and a maximum PHB accumulation contributing
to about 53% of cellular dry weight. About 4.6 g PHB were isolated from 10.6 g dried cells of strain 56, which exhibited a
weight average molar mass of 2.3 × 105 g mol−1 and a polydispersity of about 1.4.
Received: 3 December 1999 / Received revision: 22 February 2000 / Accepted: 25 February 2000 相似文献
10.
This paper examined the biodegradability of a new aliphatic polyester, polyethylene succinate (PES), at a high incubation temperature of 50°C. The distribution and population of total colonies and of PES degrading micro organisms on polymer-emulsified agar plates were determined using the plate count and clear zone methods. The PES-decomposers were present in six of 10 soil samples and the total number ranged from 2.0×104 to 2.2×106 c.f.u./g of samples. Degrading microorganisms constituted between 20 and 80% of the total colonies on PES–agar plates. A single PES-degrading strain, TT96, was isolated and tested for its biodegrading capacity on PES powder and on other aliphatic polyesters: poly(beta-hydroxybutyrate) (PHB), polycaprolactone (PCL), poly(butylene succinate) (PBS), and poly(L-lactide) (PLA). Degraded films of PES and PBS were presented and compared using scanning electron microscopy. Strain TT96 was able to create clear zones on all the polymers used, except on PHB-agar plates. Liquid culture test after 2 weeks showed that TT96 completely degraded PCL powder but had very little activity on other samples. Scanning electron micrograph confirmed the microbial attack of TT96 on PES and PBS films. PES film surfaces were degraded more uniformly compared to PBS films which were decomposed only in some parts. 相似文献
11.
Microbial Degradation of an Aliphatic Polyester with a High Melting Point, Poly(Tetramethylene Succinate) 总被引:4,自引:1,他引:3
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The biodegradability of poly(tetramethylene succinate) (PTMS), a synthetic aliphatic polyester with a high melting point, was evaluated. The ecological study showed that the distribution of PTMS-degrading microorganisms in soil environments was quite restricted compared with the distribution of microorganisms that degrade poly((epsilon)-caprolactone) (PCL), a polyester with a low melting point. However, in soil samples in which the formation of a clear zone was observed, PTMS-degrading microorganisms constituted 0.2 to 6.0% of the total number of microorganisms, which is very close to the percentage (0.8 to 8.0%) observed for PCL-degrading microorganisms. Five strains were isolated from colonies which formed distinct clear zones on agar plates with emulsified PTMS. In liquid cultures of the isolates with ground PTMS powder, strain HT-6, an actinomycete, showed the highest PTMS degrading activity. It assimilated about 60% of the ground PTMS powder after 8 days of cultivation. When a PTMS emulsion was used, a higher degradation rate was observed and more than 90% of the PTMS was assimilated in 6 days. PTMS degradation products were analyzed by gas chromatography, and it was found that 1,4-butanediol, 4-hydroxy n-butyrate, and succinic acid accumulated during cultivation. Degradation of PTMS film by the strain occurred in two steps: fragmentation and then the formation of hemispherical holes on the surface of the film. Strain HT-6 was also able to assimilate PCL and poly((beta)-hydroxybutyrate) (PHB). The crude enzyme showed a wide range of substrate specificity, being able to degrade low-molecular-weight PTMS, PCL, PHB, and even high-molecular-weight PTMS. 相似文献
12.
In a limited-scale survey, 55 soil streptomycetes were screened for the accumulation of poly (3-hydroxybutyrate) [PHB]. Only
18% of the isolates accumulated PHB ranging between 1.9–7.8% of the dry biomass. The promising isolate DBCC-719, identified
as Streptomyces griseorubiginosus, accumulated PHB amounting to 9.5% of the mycelial dry mass in the early stationary phase when grown in chemically defined
medium with 2% (wt/vol) glucose as the sole source of carbon. Nitrogen-limiting conditions were inhibitory to growth and PHB
accumulation. The isolated polymer was highly soluble in chloroform, gave a sharp peak at 235 nm on digestion with concentrated
H2SO4, and had a characteristic infrared spectrum.
Received: 26 March 1999 / Accepted: 3 May 1999 相似文献
13.
Aamer Ali Shah Satoshi Kato Noboru Shintani Numbi Ramudu Kamini Toshiaki Nakajima-Kambe 《Applied microbiology and biotechnology》2014,98(8):3437-3447
Biodegradable plastics (BPs) have attracted much attention since more than a decade because they can easily be degraded by microorganisms in the environment. The development of aliphatic-aromatic co-polyesters has combined excellent mechanical properties with biodegradability and an ideal replacement for the conventional nondegradable thermoplastics. The microorganisms degrading these polyesters are widely distributed in various environments. Although various aliphatic, aromatic, and aliphatic-aromatic co-polyester-degrading microorganisms and their enzymes have been studied and characterized, there are still many groups of microorganisms and enzymes with varying properties awaiting various applications. In this review, we have reported some new microorganisms and their enzymes which could degrade various aliphatic, aromatic, as well as aliphatic-aromatic co-polyesters like poly(butylene succinate) (PBS), poly(butylene succinate)-co-(butylene adipate) (PBSA), poly(ε-caprolactone) (PCL), poly(ethylene succinate) (PES), poly(l-lactic acid) (PLA), poly(3-hydroxybutyrate) and poly(3-hydoxybutyrate-co-3-hydroxyvalterate) (PHB/PHBV), poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT), poly(butylene adipate-co-terephthalate (PBAT), poly(butylene succinate-co-terephthalate) (PBST), and poly(butylene succinate/terephthalate/isophthalate)-co-(lactate) (PBSTIL). The mechanism of degradation of aliphatic as well as aliphatic-aromatic co-polyesters has also been discussed. The degradation ability of microorganisms against various polyesters might be useful for the treatment and recycling of biodegradable wastes or bioremediation of the polyester-contaminated environments. 相似文献
14.
A total of 338 aerobic heterotrophic bacterial strains were isolated from Arctic sea ice, Canada Basin (77°30′N–80°12′N).
The capability of the isolates to produce protease, lipase, amylase, chitinase, β-galactosidase, cellulase and/or agarase
was investigated. Isolates that were able to degrade tributyrin, skim milk, starch, lactose and chitin accounted for 71.6,
65.7, 38.5, 31.6 and 16.9% of sea ice strains, respectively. Lipase producers and/or protease producers were phylogenetically
widespread among the isolated strains. Starch and/or lactose hydrolytic strains were mainly distributed among Colwellia, Marinomonas, Pseudoalteromonas, Pseudomonas and Shewanella isolates. Pseudoalteromonas tetraodonis, Pseudoalteromonas
elyakovii, Bacillus firmus and Janibacter melonis isolates all have the ability to degrade chitin. Only some strains belonging to Pseudoalteromonas genus scored positive for agarase (6) and cellulose (9). The temperature dependences for lipase activities were determined
for five psychrophilic and six psychrotolerant bacteria. At low temperatures, the psychrophilic bacterial lipase activity
was not significantly higher than psychrotolerant bacterial lipase, though all lipases showed remarkably high activity with
10–36% residual activity at 0°C. 相似文献
15.
Kathryn L. Houmiel Steven Slater Debra Broyles Laura Casagrande Susan Colburn Kathleen Gonzalez Timothy A. Mitsky Steven E. Reiser Devang Shah Nancy B. Taylor Mintien Tran Henry E. Valentin Kenneth J. Gruys 《Planta》1999,209(4):547-550
Polyhydroxyalkanoates (PHAs) comprise a class of biodegradable polymers which offer an environmentally sustainable alternative
to petroleum-based plastics. Production of PHAs in plants is attractive since current fermentation technology is prohibitively
expensive. The PHA homopolymer poly(β-hydroxybutyrate) (PHB) has previously been produced in leaves of Arabidopsis thaliana (Nawrath et al., 1994, Proc Natl Acad Sci USA 91: 12760–12764). However, Brassica napus oilseed may provide a better system for PHB production because acetyl-CoA, the substrate required in the first step of PHB
biosynthesis, is prevalent during fatty acid biosynthesis. Three enzymatic activities are needed to synthesize PHB: a β-ketothiolase,
an acetoacetyl-CoA reductase and a PHB synthase. Genes from the bacterium Ralstonia eutropha encoding these enzymes were independently engineered behind the seed-specific Lesquerella fendleri oleate 12-hydroxylase promoter in a modular fashion. The gene cassettes were sequentially transferred into a single, multi-gene
vector which was used to transform B. napus. Poly(β-hydroxybutyrate) accumulated in leukoplasts to levels as high as 7.7% fresh seed weight of mature seeds. Electron-microscopy
analyses indicated that leukoplasts from these plants were distorted, yet intact, and appeared to expand in response to polymer
accumulation.
Received: 26 May 1999 / Accepted: 16 June 1999 相似文献
16.
Kim BS 《Enzyme and microbial technology》2000,27(10):774-777
Two inexpensive substrates, starch and whey were used to produce poly(3-hydroxybutyrate) (PHB) in fed-batch cultures of Azotobacter chroococcum and recombinant Escherichia coli, respectively. Oxygen limitation increased PHB contents in both fermentations. In fed-batch culture of A. chroococcum, cell concentration of 54 g l−1 with 46% PHB was obtained with oxygen limitation, whereas 71 g l−1 of cell with 20% PHB was obtained without oxygen limitation. The timing of PHB biosynthesis in recombinant E. coli was controlled using the agitation speed of a stirred tank fermentor. A PHB content of 80% could be obtained with oxygen limitation by increasing the agitation speed up to only 500 rpm. 相似文献
17.
Maple sap, an abundant natural product especially in Canada, is rich in sucrose and thus may represent an ideal renewable
feedstock for the production of a wide variety of value-added products. In the present study, maple sap or sucrose was employed
as a carbon source to Alcaligenes latus for the production of poly-β-hydroxybutyrate (PHB). In shake flasks, the biomass obtained from both the sap and sucrose were
4.4 ± 0.5 and 2.9 ± 0.3 g/L, and the PHB contents were 77.6 ± 1.5 and 74.1 ± 2.0%, respectively. Subsequent batch fermentation
(10 L sap) resulted in the formation of 4.2 ± 0.3 g/L biomass and a PHB content of 77.0 ± 2.6%. The number average molecular
weights of the PHB produced by A. latus from maple sap and pure sucrose media were 300 ± 66 × 103 and 313 ± 104 × 103 g/mol, respectively. Near-infrared, 1H magnetic resonance imaging (MRI), and 13C-MRI spectra of the microbially produced PHB completely matched those obtained with a reference material of poly[(R)-3-hydroxybutyric
acid]. The polymer was found to be optically active with [α]25
D equaled to −7.87 in chloroform. The melting point (177.0°C) and enthalpy of fusion (77.2 J/g) of the polymer were also in
line with those reported, i.e., 177°C and 81 J/g, respectively. 相似文献
18.
Isolation of bacteria producing polyhydroxyalkanoates (PHA) from municipal sewage sludge 总被引:1,自引:0,他引:1
S. Vishnuvardhan Reddy M. Thirumala T. V. Kishore Reddy S. K. Mahmood 《World journal of microbiology & biotechnology》2008,24(12):2949-2955
Bacterial isolates from sludge samples collected at a local municipal sewage treatment plant were screened for bacteria producing
polyhydroxyalkanoates (PHA). Initially Sudan black B staining was performed to detect lipid cellular inclusions. Lipid-positive
isolates were then grown in a nitrogen limitation E2 medium containing 2% (w/v) glucose to promote accumulation of PHA before
the subsequent staining with Nile blue A. The positive isolates were quantified initially with a u.v. spectrophotometer, for
a very large number of isolates (105) and among them high PHA-producing isolates (15) were selected and were confirmed by
gas chromatographic analysis. The GC analysis showed the polymers produced by 13 of the selected isolates to be polyhydroxybutyrate
(PHB), and the remaining two isolates produced polyhydroxybutyrate-co-hydroxyvalerate (PHB-co-HV) copolymer. The proportion
of the PHA-positive bacterial isolates showed variability in the number of PHA accumulators during various months. The correlation
of PHB production with the cell dry weight (CDW) was found to be statistically significant. The metabolism of PHB in these
selected 15 isolates was studied using the Nile blue A staining, which showed an initial increase in the fluorescence followed
by a decline, on further incubation. All the selected 15 isolates were classified to genus level by studying their morphological
and biochemical characteristics. There were seven Bacillus species, three Pseudomonas species, two Alcaligenes species, two Aeromonas species, and one Chromobacterium species. 相似文献
19.
The diversity of heterotrophic bacterial isolates of three commercial and two homemade composts was studied. The commercial
composts were produced from poultry litter (PC), sewage sludge (SC), municipal solid waste (MC), and homemade composts (thermal
compost [DC] and vermicompost [VC]) from food wastes. The taxonomic and physiological diversity of the heterotrophic culturable
bacteria was assessed using phenotypic and genotypic characterization and the analysis of the partial 16S rRNA gene sequence.
Composts DC and SC presented the higher genotypic diversity, as could be inferred from the number of distinct genotypic patterns
observed, 28 and 21, respectively. Gram-positive bacteria, mainly Firmicutes, were predominant in all the composts. Some organisms related with taxa rarely reported in composts, as Rhodanobacter spathiphylli, Moraxella osloensis, Lysobacter, Corynebacterium, Pigmentiphaga kullae, and new taxa were also isolated. The highest relative proportion of isolates able to degrade starch was found in compost
SC (>70%), to degrade gelatine in compost DC (>70%), to degrade Tween 80 in compost PC (>90%), and to degrade poly-epsilon-caprolactones
in compost DC (>80%). Compost MC presented the lowest relative proportions of isolates able to degrade starch (<25%), gelatine
(<20%), and poly-epsilon-caprolactone (<40%). When compared with the others, the homemade composts presented higher relative
proportions of Gram-positive isolates able to inhibit the target organisms Staphylococcus aureus, Enterococcus
faecalis, Escherichia coli, or Pseudomonas aeruginosa. In compost MC, none of the Gram-positive isolates was able to inhibit those targets. 相似文献
20.
Stanislav Obruca Ivana Marova Marie Stankova Ludmila Mravcova Zdenek Svoboda 《World journal of microbiology & biotechnology》2010,26(7):1261-1267
Exposition of Cupriavidus necator to ethanol or hydrogen peroxide at the beginning of the stationary phase increases poly(3-hydroxybutyrate) (PHB) yields about
30%. Hydrogen peroxide enhances activity of pentose phosphate pathway that probably consequently increases intracellular ratio
NADPH/NADP+. This effect leads to stimulation of the flux of acetyl-CoA into PHB biosynthetic pathway and to an increase of enzymatic
activities of β-ketothiolase and acetoacetyl-CoA reductase while activity of PHB synthase remains uninfluenced. During ethanol
metabolisation, in which alcohol dehydrogenase is involved, acetyl-CoA and reduced coenzymes NAD(P)H are formed. These metabolites
could again slightly inhibit TCA cycle while flux of acetyl-CoA into PHB biosynthetic pathway is likely to be supported. As
a consequence of TCA cycle inhibition also less free CoA is formed. Similarly with hydrogen peroxide, activities of β-ketothiolase
and acetoacetyl-CoA reductase are increased which results in over-production of PHB. Molecular weight of PHB produced under
stress conditions was significantly higher as compared to control cultivation. Particular molecular weight values were dependent
on stress factor concentrations. This could indicate some interconnection among activities of β-ketothiolase, acetoacetyl-CoA
reductase and PHB molecular weight control in vivo. 相似文献