Effects of hydrothermal parameters on the physicochemical property and photocatalytic degradation of bisphenol A of Ti-based TiO2 nanomaterials

Dong Li,Yunzhou Chen,Jialin Jia,Haiyang He,Wei Shi,Jianghua Yu,Jun Ma 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.109 No.-

Effects of hydrothermal parameters on morphology, crystal structure, light absorption, separation efficiencyof photo-generated charge carriers, and photocatalytic removal of Bisphenol A (BPA) of Ti-basedTiO2 nanomaterials were systematically investigated. Through changing hydrothermal parameters,TiO2 nanobelts, TiO2 nanosheets and TiO2 nanowires were prepared. With increasing NaOH concentration,hydrothermal temperature, and hydrothermal time, more TiO2 with (101) crystal plane grew onTi substrate, resulting in higher crystallinity. The UV-light absorption enhanced with increasing NaOHconcentration, but decreased with improving hydrothermal temperature, hydrothermal time, and HClconcentration. Variation of UV-light absorption was mainly affected by morphology, and UV-light absorptionof TiO2 nanomaterials with different morphologies was arranged in order ofnanobelts > nanosheets > nanowires. The hydrothermal growth of TiO2 nanomaterials on Ti plate conformedto Ostwald ripening mechanism. Variation trend of photo-generated current was consistent withthat of BPA degradation, they both first increased and then decreased within investigated range. The optimalNaOH concentration, hydrothermal temperature, hydrothermal time, and HCl washing concentrationwere 1 M, 170℃, 28 h, and 0.1 M, respectively. Under this condition, Ti-based TiO2 nanosheets exhibitedthe highest BPA removal efficiency (92.7%), which was due to highly ordered nanosheet structure, goodcrystallinity, appropriate UV-light absorption and high separation efficiency of electron-hole pairs.

Enhancement of the electro-Fenton degradation of organic contaminant by accelerating Fe3+/Fe2+ cycle using hydroxylamine

Dong Li,Tong Zheng,Jianghua Yu,Haiyang He,Wei Shi,Jun Ma 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.105 No.-

The Electro-Fenton process can generate reactive oxygen species capable of oxidizing refractory organiccontaminants. However, low regeneration efficiency of Fe2+ restricts its application. Herein, hydroxylamine(HA) was added into the Electro-Fenton (HA/Electro-Fenton) process to accelerate the transformationof Fe3+ to Fe2+. Using dimethyl phthalate (DMP) as target contaminant, the HA/Electro-Fenton systemalleviated the two-stage reaction process and accelerated the removal of DMP in the pH range of 2.0–6.0. With improving DMP concentration from 5 mg L-1 to 50 mg L-1, their degradation rate increased in theHA/Electro-Fenton system, while decreased in the Electro-Fenton system. The addition of HA had negligibleeffect on electro-generation of H2O2, but facilitate the redox cycle of Fe3+/Fe2+ and the generation ofhydroxyl radicals, thus improving the degradation of DMP. The final transformation products of HA wereN2, N2O, and NO3. The presence of PO4 3 improved DMP degradation, while Cl and organic matters inhibitedDMP removal in varying degrees. This study provided useful reference to solve the low efficiency ofFe3+/Fe2+ cycle and expand the pH application range in the Electro-Fenton process.

Enzymatic Transformation of 2-O-α-D-glucopyranosyl-L-ascorbic Acid by α-cyclodextrin Glucanotransferase from Recombinant Escherichia coli

Zichen Zhang,Jianghua Li,Long Liu,Jun Sun,Zhaozhe Hua,Guocheng Du,Jian Chen 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.1

The study aimed to produce 2-O-α-D-glucopyranosyl-L-ascorbic acid (AA-2G) via the transglycosylation reaction by α-cyclodextrin glucanotransferase (α-CGTase) from recombinant Escherichia coli with L-ascorbic acid (AA) and β-cyclodextrin (β-CD) as the substrates. Liquid chromatography-tandem mass spectrometry analysis was conducted for AA-2G identification, and the glucoamylase treatment was carried out to produce AA-2G from AA-2-oilgosaccharides. The optimal temperature and pH for the enzymatic AA-2G production were 37°C and 5.5,respectively, and the optimal α-CGTase concentration and substrate mass ratio (AA:β-CD) for AA-2G synthesis were 160 U/mL and 1:1, respectively. At these optimal process conditions, maximal AA-2G production reached 13 g/L. This is the first report regarding the process optimization of enzymatic AA-2G production by α-CGTase from recombinant E. coli. The results may be useful for the industrial scale production of AA-2G.

Modeling and optimization of cutinase production by recombinant Escherichia coli based on statistical experimental designs

Wenyi Tao,Jianghua Li,Long Liu,Jing Wu,Jun Sun,Guocheng Du,Jian Chen 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.4

Statistics-based experiment designs were used to optimize the culture medium (glucose, yeast extract, IPTG,tween-60, and CaCl2) for cutinase production by recombinant Escherichia coli. A 25-1 fractional factorial design augmented with center points revealed that glucose, yeast extract, and IPTG were the most significant factors, whereas the other factors were not important within the levels tested. The method of steepest ascent was used to approach the proximity of optimum, followed by a central composite design to develop a response surface for culture condition optimization. The optimum culture medium for cutinase production was found to be: glucose 33. 92 g/L, yeast extract 30.92 g/L,and IPTG 0.76 g/L. A cutinase production of 145.27±1.5 U/mL, which was in agreement with the prediction, was observed in triplicate verification experiments. The results obtained here verified the effectiveness of the applied methodology and may be helpful for cutinase production on an industrial scale.

Engineering of Biosynthesis Pathway and NADPH Supply for Improved L-5-Methyltetrahydrofolate Production by Lactococcus lactis

( Chuanchuan Lu ),( Yanfeng Liu ),( Jianghua Li ),( Long Liu ),( Guocheng Du ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 Journal of microbiology and biotechnology Vol.31 No.1

L-5-methyltetrahydrofolate (5-MTHF) is one of the biological active forms of folate, which is widely used as a nutraceutical. However, low yield and serious pollution associated with the chemical synthesis of 5-MTHF hampers its sustainable supply. In this study, 5-MTHF production was improved by engineering the 5-MTHF biosynthesis pathway and NADPH supply in Lactococcus lactis for developing a green and sustainable biosynthesis approach. Specifically, overexpressing the key rate-limiting enzyme methylenetetrahydrofolate reductase led to intracellular 5-MTHF accumulation, reaching 18 μg/l. Next, 5-MTHF synthesis was further enhanced by combinatorial overexpression of 5-MTHF synthesis pathway enzymes with methylenetetrahydrofolate reductase, resulting in 1.7-fold enhancement. The folate supply pathway was strengthened by expressing folE encoding GTP cyclohydrolase I, which increased 5-MTHF production 2.4-fold to 72 μg/l. Furthermore, glucose-6-phosphate dehydrogenase was overexpressed to improve the redox cofactor NADPH supply for 5- MTHF biosynthesis, which led to a 60% increase in intracellular NADPH and a 35% increase in 5-MTHF production (97 μg/l). To reduce formation of the by-product 5-formyltetrahydrofolate, overexpression of 5-formyltetrahydrofolate cyclo-ligase converted 5-formyltetrahydrofolate to 5,10-methyltetrahydrofolate, which enhanced the 5-MTHF titer to 132 μg/l. Finally, combinatorial addition of folate precursors to the fermentation medium boosted 5-MTHF production, reaching 300 μg/l. To the best of our knowledge, this titer is the highest achieved by L. lactis. This study lays the foundation for further engineering of L. lactis for efficient 5-MTHF biosynthesis.

Combinatorial Fine-Tuning of Phospholipase D Expression by Bacillus subtilis WB600 for the Production of Phosphatidylserine

( Tingting Huang ),( Xueqin Lv ),( Jianghua Li ),( Hyun-dong Shin ),( Guocheng Du ),( Long Liu ) 한국미생물 · 생명공학회 2018 Journal of microbiology and biotechnology Vol.28 No.12

Phospholipase D has great commercial value due to its transphosphatidylation products that can be used in the food and medicine industries. In order to construct a strain for use in the production of PLD, we employed a series of combinatorial strategies to increase PLD expression in Bacillus subtilis WB600. These strategies included screening of signal peptides, selection of different plasmids, and optimization of the sequences of the ribosome-binding site (RBS) and the spacer region. We found that using the signal peptide amyE results in the highest extracellular PLD activity (11.3 U/ml) and in a PLD expression level 5.27-fold higher than when the endogenous signal peptide is used. Furthermore, the strain harboring the recombinant expression plasmid pMA0911-PLD-amyE-his produced PLD with activity enhanced by 69.03% (19.1 U/ml). We then used the online tool \RBS Calculator v2.0 to optimize the sequences of the RBS and the spacer. Using the optimized sequences resulted in an increase in the enzyme activity by about 26.7% (24.2 U/ml). In addition, we found through a transfer experiment that the retention rate of the recombinant plasmid after 5 generations was still 100%. The final product, phosphatidylserine (PS), was successfully detected, with transphosphatidylation selectivity at 74.6%. This is similar to the values for the original producer.

Ultrasound guided breast cancer surgery & VABB experiences in China

Chenguang Zhang,Yongtao Li,Xiowen Wang,Weihua Jiang,Lina Yi,Jianghua Ou 대한외과학회 2016 대한외과학회 학술대회 초록집 Vol.2016 No.11

Enhanced 2,5-Furandicarboxylic Acid (FDCA) Production in Raoultella ornithinolytica BF60 by Manipulation of the Key Genes in FDCA Biosynthesis Pathway

( Haibo Yuan ),( Yanfeng Liu ),( Xueqin Lv ),( Jianghua Li ),( Guocheng Du ),( Zhongping Shi ),( Long Liu ) 한국미생물 · 생명공학회 2018 Journal of microbiology and biotechnology Vol.28 No.12

The compound 2,5-furandicarboxylic acid (FDCA), an important bio-based monomer for the production of various polymers, can be obtained from 5-hydroxymethylfurfural (HMF). However, efficient production of FDCA from HMF via biocatalysis has not been well studied. In this study, we report the identification of key genes that are involved in FDCA synthesis and then the engineering of Raoultella ornithinolytica BF60 for biocatalytic oxidation of HMF to FDCA using its resting cells. Specifically, previously unknown candidate genes, adhP3 and alkR, which were responsible for the reduction of HMF to the undesired product 2,5- bis(hydroxymethyl)furan (HMF alcohol), were identified by transcriptomic analysis. Combinatorial deletion of these two genes resulted in 85.7% reduction in HMF alcohol formation and 23.7% improvement in FDCA production (242.0 mM). Subsequently, an aldehyde dehydrogenase, AldH, which was responsible for the oxidation of the intermediate 5-formyl-2-furoic acid (FFA) to FDCA, was identified and characterized. Finally, FDCA production was further improved by overexpressing AldH, resulting in a 96.2% yield of 264.7 mM FDCA. Importantly, the identification of these key genes not only contributes to our understanding of the FDCA synthesis pathway in R. ornithinolytica BF60 but also allows for improved FDCA production efficiency. Moreover, this work is likely to provide a valuable reference for producing other furanic chemicals.

Winding strategy of driving cable based on dynamic analysis of deployment for deployable antennas

Yiqun Zhang,Dongwu Yang,Zihan Sun,Na Li,Jianghua Du 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.11

An optimization method for the winding strategy of the driving cable is proposed based on a dynamic analysis of the AstroMesh antenna deployment. First, considering the effects of the cable net and friction, the driving force for deployment is deduced according to energy conservation. Thereafter, an optimization model is constructed, with the objective of minimum deployment driving power, using design variables consisting of control parameters of the winding length curve of the driving cable; this curve is described by the Bezier curve. Moreover, corresponding to the winding process of the driving cable before and after optimization, deployment experiments for a 2-m aperture deployable antenna prototype are conducted. Finally, the validity and rationality of the optimization method are verified by comparing the simulation and experimental results.

Comparative Study of L-phenylalanine Production in the Growing and Stationary Phases during High Cell Density Cultivation of an Auxotrophic Escherichia coli

Jing Wang,Long Liu,Haiyan Zhou,Jianghua Li,Guocheng Du,Jian Chen 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.5

High cell density cultivation was investigated for L-phenylalanine (L-Phe) production by an L-tyrosine (L-Tyr) auxotrophic Escherichia coli WSH-BR165 (pAPB03). Dual exponential feeding of L-Tyr and glucose was adopted to achieve high cell density cultivation. The control was completed without dual feeding. The processes where dual feeding and induction were commenced together and those where induction began after dual feeding were studied and compared. The results indicated that the former dual feeding mode was most favorable for enhanced L-Phe production. With an optimal specific growth rate of 0.09/h during the dual exponential feeding period, the maximum dry cell weight reached 43.16 g/L (3.04 times that of the control) with a final L-Phe titer of 44.53 g/L (1.06 times that of the control) and an L-Phe productivity of 1.484 g/L/h (1.69 times that of the control). High cell density cultivation via the feeding of L-Tyr and glucose exponentially after the induction point proved to be an efficient approach to enhance L-Phe production.