https://nova.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:37008 Wed 05 Aug 2020 14:09:13 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:47840 Wed 01 Feb 2023 15:41:54 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:41116 Burkholderia sp. adapt to high phenol concentrations, the strain’s tolerance ability and time-course transcriptome in combination with cell phenotype were evaluated. Surprisingly, Burkholderia sp. still grew normally after a long adaptation to a relatively high phenol concentration (1500 mg/L) and exhibited some time-dependent changes compared to unstressed cells prior to the phenol addition. Time-course transcriptome analysis results revealed that the mechanism of adaptations to phenol was an evolutionary process that transitioned from tolerance to positive degradation through precise gene regulation at appropriate times. Specifically, basal stress gene expression was upregulated and contributed to phenol tolerance, which involved stress, DNA repair, membrane, efflux pump and antioxidant protein-coding genes, while a phenol degradation gene cluster was specifically induced. Interestingly, both the catechol and protocatechuate branches of the β-ketoadipate pathway contributed to the early stage of phenol degradation, but only the catechol branch was used in the late stage. In addition, pathways involving flagella, chemotaxis, ATP-binding cassette transporters and two-component systems were positively associated with strain survival under phenolic stress. This study provides the first insights into the specific response of Burkholderia sp. to high phenol stress and shows potential for application in remediation of polluted environments.]]> Tue 26 Jul 2022 09:30:25 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:26517 Thu 05 Oct 2023 16:40:22 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:31244 Zymomonas mobilis ZM4 gnlΔ, were investigated via growth inhibitory assay and biotransformation of glucose and fructose into gluconolactone and sorbitol, respectively. The results of ethanol fermentation studies performed in the presence of high concentration of glucose (>200 g l⁻¹) under fermentative or aerobic conditions indicated that a significant reduction of volumetric ethanol productivity from the strain of ZM4 gnlΔ was noticeable due to the reduced rates of specific growth, sugar uptake, and biomass yield as compared with those of the parental strain ZM4. The biotransformation prepared at pH 6.0 using the permeabilized cell indicated that gluconic acid from ZM4 gnlΔ was still produced as a major product (67 g l⁻¹) together with sorbitol (65 g l⁻¹) rather than gluconolactone after 24 h. Only small amount of gluconolactone was transiently overproduced up to 9 g l⁻¹, but at the end of biotransformation, all gluconolactone were oxidized into gluconic acid. This indicated that autolysis of gluconolactone at the pH led to such results despite under gluconolactonase inactivation conditions. The physiological characteristics of ZM4 gnlΔ was further investigated under various stress conditions, including suboptimal pH (3.5~6.0), temperature (25~40 °C), and presence of growth inhibitory molecules including hydrogen peroxide, ethanol, acetic acid, furfural, and so forth. The results indicated that ZM4 gnlΔ was more susceptible at high glucose concentration, low pH of 3.5, and high temperature of 40 °C and in the presence of 4 mM H₂O₂ comparing with ZM4. Therefore, the results were evident that gluconolactonase in Z. mobilis contributed to industrial robustness and anti-stress regulation.]]> Sat 24 Mar 2018 08:44:01 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:37161 Mon 24 Aug 2020 16:04:57 AEST ]]>