Phenol hydroxylase (PH) plays a central role in phenol biodegradation pathways. In this study, the enzymatic activity of PH in Candida tropicalis GY8 was evaluated following phenol-induced cultivation, and oxidation products were analyzed via high-performance liquid chromatography (HPLC). Two phenol hydroxylase genes, CtPHE1 and CtPHE2 , were identified, and their expression patterns were examined using RT-qPCR. Functional analysis of the corresponding proteins was conducted by cloning and expressing the genes in Escherichia coli BL21(DE3). Enzymatic activity reached its maximum after 15 h of cultivation ( p < 0.01), and phenol conversion to catechol was verified by HPLC. RT-qPCR results indicated peak transcript levels at 10 h, with CtPHE2 showing consistently higher expression than CtPHE1 at 5, 10, and 15 h ( p < 0.01). Both recombinant proteins were capable of phenol degradation, with CtPHE2 exhibiting greater catalytic activity. These findings provide essential molecular information for advancing the understanding of phenol biodegradation mechanisms.
FeAlPO-34 molecular sieves with tunable iron contents were synthesized in a 1-butyl-3-methylimidazolium bromide [BMIm] Br ionic liquid. The added Fe 3+ was successfully incorporated into the AlPO-34 framework, which mainly presents in tetrahedral and octahedral sites in the framework, with up to 10.28 wt.% of isolated iron contents. The iron contents directly influenced the crystal size and morphology, mesoporous properties. A sample with relatively high iron contents and a hierarchical structure shows excellent catalytic performances when utilized as the catalyst of phenol hydroxylation reaction. The sample with 6.09 wt.% Fe showed a 41.55% of phenol conversion with the selectivity of 92.72 to hydroquinone and catechol.
Yan Hai,Yunxing Zhao,Yao Wang,Zhiqiang Wang,Ting Li,Jianfeng Zhang,Jing Liang
Low temperature significantly limit microbial growth and metabolism, thereby reducing the efficiency of pollutant degradation by environmental microorganisms. In this study, a hierarchical porous material (BF-PU-PI) was fabricated by the breath figure method. Through electrostatic interactions with the multifunctional groups on the microbial surface, Bacillus cereus ZWB3 was effectively assembled within the material, forming BF-PU-PI@ZWB3. Compared to ZWB3, BF-PU-PI@ZWB3 exhibited a 40% higher phenol degradation rate. Interestingly, at 15 °C, it maintained high degradation efficiency, with a 36% improvement over the ZWB3. The protective microenvironment provided by BF-PU-PI significantly enhanced the activities of key enzymes (phenol hydroxylase and catechol 1,2-dioxygenase), while alleviating intracellular oxidative stress. Furthermore, the thermal conductivity of BF-PU-PI was reduced to 0.0167-0.0333 W/(m·K) compared to PU, partially substituting for extracellular polysaccharides and free fatty acids to offer thermal insulation. This thermal regulation promoted the low-temperature metabolic activity of ZWB3 for phenol degradation. Machine learning models further predicted that BF-PU-PI@ZWB3 could sustain phenol degradation activity even at 8 °C. This hierarchical porous material acts as a “cold-resistant shelter” for microorganisms, enabling efficient biodegradation under low-temperature.
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