Detection and quantification of phenol in liquid and gas phases using a clay/dye composite

Guocheng Lv,Shiyuan Liu,Meng Liu,Libing Liao,Limei Wu,Lefu Mei,Zhaohui Li,Caofeng Pan 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.62 No.-

In this study, an organic dye lucigenin (BNMA) was successfully intercalated into the interlayer of montmorillonite (MMT) to prevent fluorescence quenching. With its enhanced fluorescent property, the composite was fabricated into solid strips for it fast and sensitive phenol detection in both liquid and gas phases. Under proper optimizations it is anticipated that the composite would show great potential for phenol determination in real world environment such as wastewater treatment industry.

Integration of wastewater treatment units and optimization of waste residue pyrolysis conditions in the brominated phenol flame retardant industry

Shiqi Liu,Xiangting Hou,Chengze Yu,Xiangrui Pan,Junhao Ma,Guocheng Liu,Chengzhi Zhou,Yanjun Xin,Qinghua Yan 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.115 No.-

Among the bromine flame retardants, tetrabromobisphenol A (TBBPA) is a highly effective flame retardantthat can be used as both reactive and additive. However, the synthesis reaction of TBBPA has alow conversion rate and many brominated phenolic organics. Therefore, there is an urgent need toremove brominated organic pollutants produced in the process of producing flame retardants to reducethe harm to the environment and human beings and to reduce production costs. In this study, an efficientprocess was developed to treat the wastewater and waste residue generated in TBBPA production process,realizing its harmless and resource utilization. In the resource utilization system, through the ingeniousdesign of solution mixing, precipitation separation, three-effect evaporation and concentration,valuable substances were extracted to realize the recovery and reuse of wastewater. In the harmless utilizationprocess of hazardous waste residue, through high-temperature pyrolysis at 500 C for 2 h afteroptimization with hypoxia-hyperoxia atmosphere modulation, it can avoid the production of dioxinsand carbon black, effectively remove the organic impurities, realize the harmlessness and obtain highqualitysodium sulfate. This paper aims to propose a simple, efficient and feasible utilization system,including the three major technological processes of TBBPA production, integrated wastewater treatmentand optimized the harmless treatment of waste residue to obtain sodium sulfate, so as to realize TBBPAgreen production. Compared with the traditional TBBPA synthesis system, wastewater and waste residuetreatment processes, the TBBPA quality is increased by 2 % and the economic cost is reduced by 10 %,which is of great significance to the development of the industry.

Influence of Culture Modes on the Microbial Production of Hyaluronic Acid by Streptococcus zooepidemicus

Long Liu,Jian Chen,Miao Wang,Jun Sun,Guocheng Du 한국생물공학회 2008 Biotechnology and Bioprocess Engineering Vol.13 No.3

The principal objective of this study was to assess the effects of culture modes including batch culture, pulse fed-batch culture, constant feeding rate fed-batch culture, and exponential fed-batch culture on the production of hyaluronic acid (HA) by Streptococcus zooepidemicus. Batch cultures had the highest levels of HA productivity, whereas fed-batch cultures were more favorable with regard to cell growth, and exponential fed-batch cultures evidenced the highest cell concentrations. A two-step culture model was proposed to enhance HA production: an exponential fed-batch culture was conducted prior to 8 h and then sucrose supplementation was applied for 8 h to start the batch fermentation of S. zooepidemicus. HA production and productivity were increased by 36 and 37% in the proposed two-step culture process as compared with that observed in the batch culture, respectively. The proposed two-step culture model can be applied in the production of secondary metabolites, and particularly of the exopolysaccharides.

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.

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.

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.

Synthesis, Crystal Structures and Properties of Two 3D Cd^II and Zn^II Complexes with a 3-Fold Interpenetrating Feature

Lin, Hongyan,Sui, Fangfang,Liu, Peng,Wang, Xiuli,Liu, Guocheng Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.7

Two new 3D coordination complexes [Cd(3-bpcd)(pht)] (1) and [Zn(3-bpcd)(pht)] (2) [3-bpcd = N,N'-bis(pyridin-3-yl)cyclohexane-1,4-dicarboxamide, $H_2pht$ = phthalic acid] have been hydrothermally synthesized. X-ray diffraction analysis reveals that the complexes 1 and 2 represent a 4-connected diamondoid topology with a 3-fold interpenetrating feature. Moreover, the fluorescent properties of complexes 1 and 2 are studied.

Enhanced Cutinase Production of Thermobifida fusca by a Two-stage Batch and Fed-batch Cultivation Strategy

Gangqiang He,Guanghua Huo,Liming Liu,Yang Zhu,Jian Chen,Guocheng Du 한국생물공학회 2009 Biotechnology and Bioprocess Engineering Vol.14 No.1

In this study, cutinase production by Thermobifida fusca WSH03-11 was investigated with mixed short-chain organic acids as co-carbon sources to demonstrate the possibility of producing high value-added products from organic wastes. T. fusca WSH03-11 was cultured with different combinations of butyrate, acetate, and lactate with a purpose of increasing cutinase activity. The optimum proportion of butyrate, acetate, and lactate was 4:1:3. In batch cultivation, acetate and lactate were consumed quickly, while the consumption of butyrate was depressed in the presence of acetate with a concentration higher than 0.5 g/L. Based on these results, a two-stage batch and fed-batch cultivation strategy was proposed: a batch culture with acetate and lactate as the co-carbon sources in the first 10 h, and then a fed-batch culture with a constant butyrate feeding rate of 12 mL/h during 11~20 h. By this two-stage cultivation strategy, cutinase activity, dry cell weight, and con-sumption rate of butyrate were increased by 70%, 103.4%, and 4.3-fold, respectively, compared to those of the batch cultivation. These results provided a novel and efficient way to produce high value-added products from organic wastes.

Biocatalytic Production of Glucosamine from N-Acetylglucosamine by Diacetylchitobiose Deacetylase

( Zhu Jiang ),( Xueqin Lv ),( Yanfeng Liu ),( Hyun-dong Shin ),( Jianghua Li ),( Guocheng Du ),( Long Liu ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.11

Glucosamine (GlcN) is widely used in the nutraceutical and pharmaceutical industries. Currently, GlcN is mainly produced by traditional multistep chemical synthesis and acid hydrolysis, which can cause severe environmental pollution, require a long prodution period but a lower yield. The aim of this work was to develop a whole-cell biocatalytic process for the environment-friendly synthesis of glucosamine (GlcN) from N-acetylglucosamine (GlcNAc). We constructed a recombinant Escherichia coli and Bacillus subtilis strains as efficient whole-cell biocatalysts via expression of diacetylchitobiose deacetylase (Dac_ph) from Pyrococcus furiosus. Although both strains were biocatalytically active, the performance of B. subtilis was better. To enhance GlcN production, optimal reaction conditions were found: B. subtilis whole-cell biocatalyst 18.6 g/l, temperature 40°C, pH 7.5, GlcNAc concentration 50 g/l and reaction time 3 h. Under the above conditions, the maximal titer of GlcN was 35.3 g/l, the molar conversion ratio was 86.8% in 3-L bioreactor. This paper shows an efficient biotransformation process for the biotechnological production of GlcN in B. subtilis that is more environmentally friendly than the traditional multistep chemical synthesis approach. The biocatalytic process described here has the advantage of less environmental pollution and thus has great potential for largescale production of GlcN in an environment-friendly manner.

Trajectory tracking control of underactuated USV based on modified backstepping approach

Dong, Zaopeng,Wan, Lei,Li, Yueming,Liu, Tao,Zhang, Guocheng The Society of Naval Architects of Korea 2015 International Journal of Naval Architecture and Oc Vol.7 No.5

This paper presents a state feedback based backstepping control algorithm to address the trajectory tracking problem of an underactuated Unmanned Surface Vessel (USV) in the horizontal plane. A nonlinear three Degree of Freedom (DOF) underactuated dynamic model for USV is considered, and trajectory tracking controller that can track both curve trajectory and straight line trajectory with high accuracy is designed as the well known Persistent Exciting (PE) conditions of yaw velocity is completely relaxed in our study. The proposed controller has further been enriched by incorporating an integral action additionally for enhancing the steady state performance and control precision of the USV trajectory tracking control system. Global stability of the overall system is proved by Lyapunov theory and Barbalat's Lemma, and then simulation experiments are carried out to demonstrate the effectiveness of the controller designed.