FOOD CHEMISTRY
·
2024
·
IF 8.5
Yinchun Liu,Fang Liu,Jianrui Liu,Jingwen Dong,Mingxia Xing,Xiangyu Chen,Ya'nan Wu,Tianxi Ai,Yongqin Zhang
Pectin depolymerase is widely utilized in various industrial sectors. However, the traditional methods for determining its enzymatic activity have limitations, such as cumbersome operations and a significant impact of enzyme solution dilution ratios on activity. The 3-methyl-2-benzothiazolinone hydrazone (MBTH) method can be employed to address these issues, but pectin precipitation and strong background commonly arise in this method. We have successfully overcome these challenges by employing a low-temperature and high-alkaline environment, and further optimized the reagent compositions and detection wavelength to improve the method. Consequently, enzyme hydrolysis follows a zero-order reaction within 60 min, which is helpful for the endpoint measurement of pectinase activity. The developed calibration curve for pectinase concentration and hydrolysis rate demonstrates linearity (R 2 = 0.9945) within the range of 2.5–15.8 mU/mL of pectinase. This method exhibits high sensitivity, accuracy, and stability, making it suitable for routine determination of pectin depolymerase activity in research and applications.
研究领域:
生物化学
·
工业酶学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED ORGANOMETALLIC CHEMISTRY
·
2019
·Vol. 33
·期 11
·e5217
·
IF 3.259
Luyao Ma,Chenxin Liu,Qingxin Guan,Wei Li
The effects of particle size and kinetics of Pt/activated carbon (AC) catalysts on catalytic oxidation of formaldehyde (HCHO) were investigated. AC, f-SiO 2 and MCM-41 were used as supports to prepare low-Pt-content catalysts using H 2 reduction. Pt/AC catalyst shows the highest activity with the largest Pt particle size. By contrast, 0.1 wt% Pt/AC reduced using KBH 4 has much higher activity than that reduced using H 2 , which can oxidize HCHO completely over 6000 ppm at 60°C in a fixed bed reactor. Transmission electron microscopy and X-ray photoelectron spectroscopy results indicate that Pt/AC-KBH 4 has larger Pt particles and lower valence state than Pt/AC-H 2 , which may be attributed to the ligand effect between Pt 4+ and the AC support. The result of O 2 temperature-programmed oxidation suggests that highly dispersed Pt 4+ ions have stronger interaction with AC support and thus are harder to be reduced by H 2 . Furthermore, Pt/AC is structure-sensitive and larger-sized Pt particles result in a high conversion of HCHO. Investigation of kinetics indicated that it is a zero-order reaction for such a high HCHO concentration condition for Pt/AC-KBH 4 .
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
INORGANICA CHIMICA ACTA
·
2024
·
IF 2.7
Junhong Gu,Zongyong Zhang,Hao Wu,Lijuan Luo,Min Zhao,Shuchang Wu
Copper (Cu)-based materials attract considerable attentions to replace noble-metal based catalysts in the aqueous reduction of highly toxic 4-nitrophenol (4-NP). However, the reported catalysts generally owned well-defined shapes and structures that commonly rely on special synthesis condition. In contrast, the randomly dispersed and sintered Cu-based counterparts were neglected. Herein, irregular and coalesced Cu catalyst was fabricated and evaluated in 4-NP reduction. The as-synthesized CuBNC800 catalyst performed best among all the prepared materials, and the aggregated Cu nanoparticles was identified as the active centers. It showed that the pre-adsorption of 4-NP played positive role in the reaction. The reaction could be completed within 12 min at 25 °C over CuBNC800 without any treatment, while the elimination of the dissolved oxygen in solution significantly reduced the reaction time to only about 2 min. Moreover, full conversion of 4-NP was even realized within 30 min when the reaction temperature reduced to only 6 °C. Different from previously reported first order reaction kinetics over Cu-based catalysts, zero order reaction kinetics was recognized over CuBNC800 in this work, which could be attributed to the limited exposed active centers.
研究领域:
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ENVIRONMENTAL ENGINEERING
·
2013
·Vol. 139
·期 9
·1222-1227
·
IF 1.399
Fangming Hu,Huihui Zhou,Zanfang Jin,Qin Sun,Zhiyan Pan,Jesse Zhu
This study investigated the biodegradation of synthetic wastewater containing 2,4,6-trichlorophenol (TCP) in a sequencing batch-fluidized bed bioreactor (SBFBBR) with waste coke particles (WCPs) as the biofilm carrier. The irregular surfaces of WCPs (diameter range from 0.6 to 2.3 mm) rendered them ideal biomass carriers. The attached biomass was 4.0–4.5 mg volatile suspended solids (VSS)/g WCPs 3 weeks after reactor start-up, and the biofilm thicknesses were 35–110 μm. Biodegradation, not adsorption-degradation or volatilization-degradation, was found to be the main TCP removal mechanism. At the initial chemical oxygen demand (COD) concentration of 300 mg L−1, removal of COD was more efficient and faster than that of TCP. The air-water ratio (ranging from 0.280 to 0.58 min−1) exerted negligible effects at dissolved oxygen (DO) concentrations above 2 mg L−1. Maximum TCP degradation (62.1% after 3 h retention time and 75.8% after 6 h) occurred at initial COD concentration of 45 mg L−1. TCP can be removed by biofilm as a sole source of carbon and energy. Furthermore, the TCP biodegradation follows zero-order reaction kinetics, with the zero-order specific biodegradation rate dependent on initial COD concentration.
研究领域:
环境工程
·
环境微生物学
·
水污染控制
·
生物反应器技术
·
有机污染物降解
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）