Modified walnut shell filter material for the enhanced removal of oil from oilfield wastewater

Xianqing Yin,Jian Zhang,Xiujun Wang,Mijia Zhu 대한환경공학회 2021 Environmental Engineering Research Vol.26 No.1

While polymer oil recovery greatly improves oil recovery, the polymer injected into the formation undergoes shearing, degradation, etc., and returns with the output liquid in the form of an anionic polyacrylamide of lower molecular weight, resulting in a production fluid. There is residual polymer, and this kind of polymer–containing wastewater is easy to contaminate the walnut shell filter in the sewage treatment process, resulting in failure of the walnut shell filter material, introduce hydrophilic sulfonic acid groups on the surface of the walnut shell filter material to lipophilic to hydrophilic of the surface. The dosage of NaHSO₃ is 10-20% of the mass fraction of walnut shell filter (mass ratio %). Reflux reaction, and the reaction time was 1-5 h; the surface wettability of the walnut shell reversed. The surface contact angle drops from 95° before modification to 36.75°-66.25°, Its surface hydrophilic oleophobic performance has been significantly improved, Treatment of 150-230 mg/L of oily sewage, filtration and oil removal rate increased from 38.05% to 89.51% by modification; Backwashing and degreasing effect is increased by 4 times.

Effects of Alkyl Chain Length on the Optoelectronic Properties and Performance of Pyrrolo-Perylene Solar Cells

Liu, Xianqing,Kim, Yu Jin,Ha, Yeon Hee,Zhao, Qinghua,Park, Chan Eon,Kim, Yun-Hi American Chemical Society 2015 ACS APPLIED MATERIALS & INTERFACES Vol.7 No.16

<P>While the impact of alkyl side-chain length on the photovoltaic properties of conjugated polymers and their performance in bulk heterojunction (BHJ) solar cells has been studied extensively, analogous studies on pyrrolo-perylene-based polymers have not received adequate attention. To explore these effects, we synthesized two copolymers based on <I>N</I>-annulated pyrrolo-perylene and consisting of cyano group substituents on thiophene vinylene thiophene units with two different alkyl groups of 2-decyltetradecyl and 7-decylnonadecyl, and we studied them with regard to chemical structure and photovoltaic performance. UV–vis spectroscopy and cyclic voltammetry studies showed that variations in alkyl chain length affect crystallization, light absorption, and the highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels. These factors have a pronounced impact on the morphology of BHJ thin films and their charge carrier separation and transportation characteristics, which, in turn, influences photovoltaic properties.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2015/aamick.2015.7.issue-16/acsami.5b01444/production/images/medium/am-2015-01444m_0008.gif'></P>

Responses of Soil Bacterial and Fungal Communities to Organic and Conventional Farming Systems in East China

( Hanlin Zhang ),( Xianqing Zheng ),( Naling Bai ),( Shuangxi Li ),( Juanqin Zhang ),( Weiguang Lv ) 한국미생물생명공학회(구 한국산업미생물학회) 2019 Journal of microbiology and biotechnology Vol.29 No.3

Organic farming is considered an effective form of sustainable agricultural management. However, understanding of soil microbial diversity and composition under long-term organic and conventional farming is still limited and controversial. In this study, the Illumina MiSeq platform was applied to investigate the responses of soil bacterial and fungal diversity and compositions to organic farming (OF) and improved conventional farming (CF, applied straw retention) in the rice-wheat rotation system. The results highlighted that the alpha diversity of microbial communities did not differ significantly, except for higher bacterial diversity under OF. However, there were significant differences in the compositions of the soil bacterial and fungal communities between organic and conventional farming. Under our experimental conditions, through the ecological functional analysis of significant different or unique bacterial and fungal taxonomic members at the phyla and genus level, OF enhanced nitrogen, sulfur, phosphorus and carbon dynamic cycling in soil with the presence of Nodosilinea, Nitrospira, LCP-6, HB118, Lyngbya, GOUTA19, Mesorhizobium, Sandaracinobacter, Syntrophobacter and Sphingosinicella, and has the potential to strengthen soil metabolic ability with Novosphingobium. On the other hand, CF increased the intensity of nitrogen cycling with Ardenscatena, KD1-23, Iamia, Nitrosovibrio and Devosia, but enriched several pathogen fungal members, including Coniochaeta, Corallomycetella, Cyclaneusma, Cystostereum, Fistulina, Curvularia and Dissoconium.

Effects of Intercropping on Soil Nutrients and Enzyme Activities in Continuous Taro Cropping Fields

Hanlin Zhang,Xianqing Zheng,Yifei Wang,Ke Song,Shuangxi Li,Juanqin Zhang,Qiyong He,Dawei Yuan,Weiguang Lv 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

A high-performance solution-processed small molecule: alkylselenophene-substituted benzodithiophene organic solar cell

백장열,조철성,김명종,( Xianqing Liu ),박광훈,김유진,박찬언,김윤희 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1

A solution-processed alkylselenophene-substituted benzodithiophene (BDT) small molecule, namely, BDTSe-TTPD, with broad absorption and suitable energy levels was synthesized. The widely used solvents o-dichlorobenzene (o-DCB), chlorobenzene (CB) or chloroform (CF) were used as the spin-coating solvent, to fabricate efficient photovoltaic devices with BDTSe-TTPD as the donor material and PC₇₁BM as the acceptor. Devices made from a CF solution demonstrated better performance in terms of short-circuit current, fill factor and power conversion efficiency, as compared to the devices made from the o-DCB and CB solutions. Finally, by optimizing the thickness of the active layer, a power conversion efficiency of 4.37% was achieved on devices with an area of 0.09 cm², under 100 mW cm² of simulated AM 1.5 irradiation.

Expression and Characterization of a New L-amino Acid Oxidase AAO Producing α-ketoglutaric Acid from L-glutamic Acid

Rao Ben,Liao Xianqing,Liu Fang,Chen Wei,Zhou Ronghua,Ma Lixin,Wang YaPing 한국생물공학회 2019 Biotechnology and Bioprocess Engineering Vol.24 No.6

L-amino acid oxidase (AAO) was reported to be capable of converting L-glutamic acid to α-aketoglutaric acid (α-KG). The sequence of AAO from Kitasatospora cheerisanensis was synthesized based on Pichia pastoris codon-usage preferences. AAO gene was cloned into plasmid pPICZα which was transformed into P. pastoris. Next, multi-copy expression plasmids were constructed by using plasmid pHBM905BDM. High-density fermentation was performed and the recombinant enzyme was characterized. The conversion conditions were optimized. By using Escherichia coli expression system, no soluble or active AAO was obtained from two strains after fermentation and induction. We can’t obtain high-level expression of recombinant strains by using plasmid pPICZα. Therefore, we constructed multi-copy expression plasmids using plasmid pHBM905BDM. By using this plasmid, multi-copy strains were constructed and named as PAAO1, PAAO2, PAAO3, PAAO4, and PAAO5, respectively. The following results showed that expression of AAO in multicopy strains increased as designed and strain PAAO5 was chosen for high-density fermentation and enzyme activity experiments. After high-density fermentation, we achieved an AAO-expression yield of 120.8 U/mL. After temperature and pH optimization, the highest AAO activity was observed at a temperature and pH of 20°C and 6, respectively. After optimization of the conversion conditions, the average production rate of L-glutamic acid to α-KG was 3.46 g/L/h and the highest α-KG titer (103 g/L) was converted from 120 g/L L-glutamic acid. In this study, AAO was abundantly expressed by using P. pastoris expression system. The following experiments indicated that AAO is suitable for use in industrial applications.

High-level Expression of an Acidic and Thermostable Chitosanase in Pichia pastoris Using Multi-copy Expression Strains and High-celldensity Cultivation

Zhou Ronghua,Liao Xianqing,Liu Fang,Dong Qing,Chen Wei,Wang YaPing,Rao Ben 한국생물공학회 2020 Biotechnology and Bioprocess Engineering Vol.25 No.4

Chitin is a linear homopolymer of acetylated β- (1,4)-linked glucosamine residues and among the most abundant polysaccharides in the world. Here, we identified and purified a novel chitosanase (CCHA) from Aspergillus oryzae NKY2017 obtained from Hu’bei province in China. Construction of a cDNA library from this strain revealed the gene sequence subsequently expressed in Pichia pastoris and subsequent construction of multi-copy expression plasmids (CCHA1/2/3/4). The results demonstrated elevated levels of CCHA expression in multi-copy strains, with strain CCHA4 chosen for high-density fermentation and enzyme-activity experiments. High-density fermentation achieved a CCHA yield of 22,500 U/mL, and temperature and pH optimization resulted in the highest CCHA activity at 40°C and 4.0, respectively. We used this enzyme for a large-scale preparation of oligosaccharides: 4 g enzyme could convert 150 kg chitosan into oligosaccharides in 24 h at 40°C. These results demonstrated abundant CCHA expression in P. pastoris and suggested the efficacy of CCHA for use in industrial applications.

Preparation and Antioxidant Activities In Vitro of a Designed Antioxidant Peptide from Pinctada fucata by Recombinant Escherichia coli

( Yanyan Wu ),( Yongkai Ma ),( Laihao Li ),( Xianqing Yang ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.1

An antioxidant peptide derived from Pinctada fucata meat using an Alcalase2.4L enzymatic hydrolysis method (named AOP) and identified by LC-TOF-MS has promising clinical potential for generating cosmetic products that protect skin from sunshine. To date, there have been few published studies investigating the structure-activity relationship in these peptides. To prepare antioxidant peptides better and improve their stability, the design and expression of an antioxidant peptide from Pinctada fucata (named DSAOP) was studied. The peptide contains a common precursor of an expression vector containing an α-helix tandemly linked according to the BamHI restriction sites. The DNA fragments encoding DSAOP were synthesized and subcloned into the expression vector pET-30a (+), and the peptide was expressed mostly as soluble protein in recombinant Escherichia coli. Meanwhile, the DPPH radical scavenging activity, superoxide radical scavenging activity, and hydroxyl radical scavenging activity of DSAOP IC50 values were 0.136 ± 0.006, 0.625 ± 0.025, and 0.306 ± 0.015 mg/ml, respectively, with 2-fold higher DPPH radical scavenging activity compared with chemosynthesized AOP (p < 0.05), as well as higher superoxide radical scavenging activity compared with natural AOP (p < 0.05). This preparation method was at the international advanced level. Furthermore, pilot-scale production results showed that DSAOP was expressed successfully in fermenter cultures, which indicated that the design strategy and expression methods would be useful for obtaining substantial amounts of stable peptides at low costs. These results showed that DSAOP produced with recombinant Escherichia coli could be useful in cosmetic skin care products, health foods, and pharmaceuticals.

Efficient Surface Display of L-glutamate Oxidase and L-amino Acid Oxidase on Pichia pastoris Using Multi-copy Expression Strains

Rao Ben,Zhou Ronghua,Dong Qing,Liao Xianqing,Liu Fang,Chen Wei,Liu Xiaoyan,Min Yong,Wang YaPing 한국생물공학회 2020 Biotechnology and Bioprocess Engineering Vol.25 No.4

L-glutamate oxidase (GLOD) and L-amino acid oxidase (AAO) were reported to be capable of convert L-glutamic acid to α-aketoglutaric acid (α-KG). These two enzymes gene have been successfully expressed by using pHBM905BDM in Pichia pastoris to produce α-aketoglutaric acid from L-glutamic acid in our previous studies. Here these two enzymes were displayed on P. pastoris to achieve the conversion. We constructed multi-copy expression plasmids using plasmid pHBM905BDM. By using this plasmid, multi-copy strains were constructed and named as PGLOD(1-3)-AGα1 and PAAO(1-3)-AGα1, respectively. The following results showed that expression of GLOD(1-3)- AGα1 and AAO(1-3)-AGα1 in multi-copy strains increased as designed and strain PGLOD3-AGα1 and PAAO3-AGα1 was chosen for high-density fermentation and enzyme activity experiments. By using a multi-copy expression approach and high-density fermentation, we achieved a GLOD expression yield of 688.5 U/g dry cell weight and AAO expression yield of 626.7 U/g dry cell weight. By using displayed GLOD, the average production rate of L-glutamic acid to α-KG was 6.22 g/L/h and the highest α-KG titer (124.5 g/L) was converted from 135 g/L L-glutamic acid. By using displayed AAO, the average production rate of L-glutamic acid to α-KG was 5.78 g/L/h and the highest α-KG titer (115.6 g/L) was converted from 135 g/L L-glutamic acid. It showed that displaying enzymes on P. pastoris are suitable for use in industrial applications.

Purification and Characteristics of Serine Protease from the Head of Pacific White Shrimp

Yanyan Wu,Ping Wang,Laihao Li,Xianqing Yang,Shiqiang Diao 한국식품과학회 2012 Food Science and Biotechnology Vol.21 No.4

Serine protease from the head of Pacific white shrimp was purified by the following techniques: ammonium sulfate fractionation, Q-Sepharose HP ion exchange chromatography, and Sephadex G-100 gel filtration. The molecular weight was estimated as 32.8 kDa using SDSPAGE. The optimum pH and temperature of the enzyme for the hydrolysis of casein were determined to be 10.0 and 40oC. It was stable at pH range from 8.0 to 11.0 and had good thermal stability. Pb2+, Ca2+, Mg2+, Cu2+, and Mn2+could active the enzyme certainly when Zn2+and Hg2+strongly inhibited the activity. The enzyme was inhibited by the general serine protease inhibitor (PMSF) and the specific trypsin inhibitors (TLCK, SBTI). The modification of various amino acid modifiers for the purified enzyme determined that the enzyme active center included tryptophan,histidine, and serine, moreover, arginine had a certain relationship with the enzyme activity.