A simple unstructured model-based control for efficient expression of recombinant porcine insulin precursor by Pichia pastoris

Siliang Zhang,Hai-feng Hang,Wen Chen,Mei-jin Guo,Ju Chu,Ying-ping Zhuang 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.5

Based on the fact that Pichia cell growth follows a Monod equation under the condition of methanol concentration limitation, a kinetics model of recombinant methylotrophic yeast Pichia pastoris expressing porcine insulin precursor (PIP) was developed in the quasi-steady state in the induction phase. The model revealed that the relationship between specific growth rate (μ) and substrate methanol concentration was in accord with the Monod equation. The fermentation kinetic parameters maximum specific growth rate (μmax), saturation constant (Ks) and maintenance coefficient (M) were estimated to be 0.101 h−1, 0.252 g l−1, and 0.011 g MeOH g−1 DCW h−1, respectively. The unstructured model was validated in methanol induction phase with different initial cell densities. Results showed that the maximum specific protein production rate (qp.max) of 0.098 mg g−1 DCW h−1 was achieved when μ was kept at 0.016 h−1, and the maximum yield of PIP reached 0.97 g l−1, which was 1.5-fold as that of the control. Therefore, the simple Monod model proposed has proven to be a robust control system for recombinant porcine insulin precursor production by P. pastoris on pilot scale, which would be further applied on production scale.

Radix et Rhizoma Ginseng chemoprevents both initiation and promotion of cutaneous carcinoma by enhancing cell-mediated immunity and maintaining redox homeostasis

Suyun Yu,Siliang Wang,Shuai Huang,Wei Wang,Zhonghong Wei,Yushi Ding,Aiyun Wang,Shile Huang,Wenxing Chen,Yin Lu 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.4

Background: Radix et Rhizoma Ginseng (thereafter called ginseng) has been used as a medicinal herb forthousands of years to maintain people’s physical vitality and is also a noneorgan-specific cancer preventiveand therapeutic traditional medicine in several epidemiologic and preclinical studies. Owing tofew toxic side effects and strong enhancement on body immunity, ginseng has admirable applicationpotential and value in cancer chemoprevention. The study aims at investigating the chemopreventiveeffects of ginseng on cutaneous carcinoma and the underlying mechanisms. Methods: The mouse skin cancer model was induced by 7,12-dimethylbenz[a]anthracene/12-O-tetradecanoylphorbol-13-acetate. Ultraperformance liquid chromatography/mass spectrometry was used foridentifying various ginsenosides, the main active ingredients of ginseng. Comprehensive approaches(including network pharmacology, bioinformatics, and experimental verification) were used to explorethe potential targets of ginseng. Results: Ginseng treatment inhibited cutaneous carcinoma in terms of initiation and promotion. Thecontent of Rb1, Rb2, Rc, and Rd ginsenosides was the highest in both mouse blood and skin tissues. Ginseng and its active components well maintained the redox homeostasis and modulated the immuneresponse in the model. Specifically, ginseng treatment inhibited the initiation of skin cancer byenhancing T-cellemediated immune response through upregulating HSP27 expression and inhibited thepromotion of skin cancer by maintaining cellular redox homeostasis through promoting nuclear translocationof Nrf2. Conclusion: According to the study results, ginseng can be potentially used for cutaneous carcinoma as achemopreventive agent by enhancing cell-mediated immunity and maintaining redox homeostasis withmultiple components, targets, and links.

Facile Atmospheric Generation of Water Radical Cations via TiO2-Nanoneedle Arrays for Aromatic Hydrocarbon Detection Based on Corona Discharge

Dongbo Mi,Jinhaojie Cui,Siliang Kuang,Xiaofeng Dong,Haiyan Lu 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.3

Water radical cations, (H2O)n+?, have attracted considerable attention owing to their potential practical applications in analytical chemistry, structural chemistry, radiotherapy, and radiochemistry. Recently, atmospheric pressure chemical ionization has emerged as a versatile method for direct mass spectrometric analysis. Usually, H3O+ is the major proton donor during ionization and only the pseudo molecular ion peaks, instead of molecular ions are detected. In this work, (H2O)2+? ions with high oxidizability and reactivity were generated using hydrothermally grown TiO2 nanoneedle arrays in combination with a linear ion trap mass spectrometer under low operating voltage and applied to the direct mass spectrometric analysis of a mixture of volatile aromatic hydrocarbons. (H2O)2+? ions were generated with a high absolute ion current of up to 1.07???105?counts/s at atmospheric pressure. Using the generated (H2O)2+? as the primary ion permitted the tandem mass spectrometric analysis of a mixed vapor sample of aromatic hydrocarbons.

Radix et Rhizoma Ginseng chemoprevents both initiation and promotion of cutaneous carcinoma by enhancing cell-mediated immunity and maintaining redox homeostasis

Yu, Suyun,Wang, Siliang,Huang, Shuai,Wang, Wei,Wei, Zhonghong,Ding, Yushi,Wang, Aiyun,Huang, Shile,Chen, Wenxing,Lu, Yin The Korean Society of Ginseng 2020 Journal of Ginseng Research Vol.44 No.4

Background: Radix et Rhizoma Ginseng (thereafter called ginseng) has been used as a medicinal herb for thousands of years to maintain people's physical vitality and is also a non-organ-specific cancer preventive and therapeutic traditional medicine in several epidemiologic and preclinical studies. Owing to few toxic side effects and strong enhancement on body immunity, ginseng has admirable application potential and value in cancer chemoprevention. The study aims at investigating the chemopreventive effects of ginseng on cutaneous carcinoma and the underlying mechanisms. Methods: The mouse skin cancer model was induced by 7,12-dimethylbenz[a]anthracene/12-O-tetradecanoylphorbol-13-acetate. Ultraperformance liquid chromatography/mass spectrometry was used for identifying various ginsenosides, the main active ingredients of ginseng. Comprehensive approaches (including network pharmacology, bioinformatics, and experimental verification) were used to explore the potential targets of ginseng. Results: Ginseng treatment inhibited cutaneous carcinoma in terms of initiation and promotion. The content of Rb1, Rb2, Rc, and Rd ginsenosides was the highest in both mouse blood and skin tissues. Ginseng and its active components well maintained the redox homeostasis and modulated the immune response in the model. Specifically, ginseng treatment inhibited the initiation of skin cancer by enhancing T-cell-mediated immune response through upregulating HSP27 expression and inhibited the promotion of skin cancer by maintaining cellular redox homeostasis through promoting nuclear translocation of Nrf2. Conclusion: According to the study results, ginseng can be potentially used for cutaneous carcinoma as a chemopreventive agent by enhancing cell-mediated immunity and maintaining redox homeostasis with multiple components, targets, and links.

Room-temperature relaxor ferroelectricity and photovoltaic effects in tin titanate directly deposited on a silicon substrate

Agarwal, Radhe,Sharma, Yogesh,Chang, Siliang,Pitike, Krishna C.,Sohn, Changhee,Nakhmanson, Serge M.,Takoudis, Christos G.,Lee, Ho Nyung,Tonelli, Rachel,Gardner, Jonathan,Scott, James F.,Katiyar, Ram S American Physical Society 2018 Physical review. B Vol.97 No.5

<P>Tin titanate (SnTiO3) has been notoriously impossible to prepare as a thin-film ferroelectric, probably because high-temperature annealing converts much of the Sn2+ to Sn4+. In the present paper, we show two things: first, perovskite phase SnTiO3 can be prepared by atomic-layer deposition directly onto p-type Si substrates; and second, these films exhibit ferroelectric switching at room temperature, with p-type Si acting as electrodes. X-ray diffraction measurements reveal that the film is single-phase, preferred-orientation ferroelectric perovskite SnTiO3. Our films showed well-saturated, square, and repeatable hysteresis loops of around 3 mu C/cm(2) remnant polarization at room temperature, as detected by out-of-plane polarization versus electric field and field cycling measurements. Furthermore, photovoltaic and photoferroelectricity were found in Pt/SnTiO3/Si/SnTiO3/Pt heterostructures, the properties of which can be tuned through band-gap engineering by strain according to first-principles calculations. This is a lead-free room-temperature ferroelectric oxide of potential device application.</P>

In silico Analysis and Experimental Improvement of Taxadiene Heterologous Biosynthesis in Escherichia coli

Hailin Meng,Yong Wang,Qiang Hua,Siliang Zhang,Xiaoning Wang 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.2

The biosynthesis of terpenoids in heterologous hosts has become increasingly popular. Isopentenyl diphosphate (IPP) is the central precursor of all isoprenoids, and the synthesis can proceed via two separate pathways in different organisms: The 1-deoxylulose 5-phosphate (DXP)pathway and the mevalonate (MVA) pathway. In this study,an in silico comparison was made between the maximum theoretical IPP yields and the thermodynamic properties of the DXP and MVA pathways using different hosts and carbon sources. We found that Escherichia coli and its DXP pathway have the most potential for IPP production. Consequently, codon usage redesign, and combinations of chromosomal engineering and various strains were considered for optimizing taxadiene biosynthesis through the endogenic DXP pathway. A high production strain yielding 876 ± 60 mg/L taxadiene, with an overall volumetric productivity of 8.9 mg/(L × h), was successfully obtained by combining the chromosomal engineered upstream DXP pathway and the downstream taxadiene biosynthesis pathway. This is the highest yield thus far reported for taxadiene production in a heterologous host. These results indicate that genetic manipulation of the DXP pathway has great potential to be used for production of terpenoids, and that chromosomal engineering is a powerful tool for heterologous biosynthesis of natural products.

On-line Specific Growth Rate Control for Improving Reduced Glutathione Production in Saccharomyces cerevisiae

Zhi-Qiang Xiong,Mei-jin Guo,Ju Chu,Ying-ping Zhuang,Siliang Zhang 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.5

Reduced glutathione (GSH), the abundant bioactive tripeptide in most living cells, is widely used in pharmaceutical, food, and cosmetic industries. Specific growth rate (μ) is a key physiological parameter for GSH high-cell-density cultivation using microbial cell factories. Here, based on a biomass probe, an on-line μ feedback control was developed to regulate glucose feeding rate during the fed-batch phase for overproducing GSH in Saccharomyces cerevisiae. Compared with real-time μ controlled at 0.15/h, μ controlled at 0.2/h achieved yeast dry weight (120 g/L), GSH concentration (1.5 g/L), and intracellular GSH content (1.25%), which improved by 9, 150, and 129.1%, respectively. To our knowledge, this is the first report about on-line μ feedback control for GSH production. On-line μ control led to 59.38 mg/L/h of GSH productivity and 3.52 mg/g of GSH yield on glucose, which improved by 107.6 and 7.2%, respectively, in comparison with those of traditional ethanol feedback control (maintaining ethanol concentration at 1%). Taken together, the on-line μ feedback control is a promising method as an efficient alternative to conventional feed control techniques presently practiced in the GSH industry, and has the potential for the production of other valuable chemicals.

Oxygen Uptake Rate Controlling Strategy Balanced with Oxygen Supply for Improving Coenzyme Q10 Production by Rhodobacter sphaeroides

Ze-Jian Wang,Xingzi Zhang,Ping Wang,Zhiwei Sui,Meijin Guo,Siliang Zhang,Yingping Zhuang 한국생물공학회 2020 Biotechnology and Bioprocess Engineering Vol.25 No.3

The effects of different oxygen uptake rates (OUR) on the physiological metabolism of Rhodobacter sphaeroides were investigated systematically in 50 L fermenters due to the significant influence on industrial coenzyme Q10 production under oxygen supply limitation. Meanwhile, the seriously decreased oxygen transfer rate caused by the increased broth viscosity was successfully prevented with OUR-directed continuous ammonium sulfate feeding in the late fermentation phase. The statistical analysis results showed that controlling OUR constantly at 45 ± 2.2 mmol/L/h by the oxygen supply level adjustment and the continuous ammonium sulfate feeding could greatly enhance Q10 production. This OUR-Stat controlling strategy successfully achieved the maximal coenzyme Q10 production (2584 ± 82 mg/L), which was 15.4% higher than that of the control. The highest specific CoQ10 content was 25.9 mg/(g DCW)), and the yield of CoQ10 to glucose consumption was up to 19.37 mg/g. These results demonstrated that the optimal OUR-Stat controlling strategy would be effective and economical for improving the industrial CoQ10 production.

In silico Improvement of Heterologous Biosynthesis of Erythromycin Precursor 6-Deoxyerythronolide B in Escherichia coli

Hailin Meng,Zhiguo Lu,Yong Wang,Xiaoning Wang,Siliang Zhang 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.3

The heterologous biosynthesis of 6-deoxyerythronolide B (6dEB), a key intermediate in the biosynthesis of erythromycin, has recently been achieved in Escherichia coli, but the experimental product yield remains low. In this study, in silico strategies were adopted to evaluate and improve the biosynthesis of 6dEB in this strain. The theoretical capability of E. coli to produce 6dEB was first evaluated by analyzing the maximum theoretical molar yield (MTMY) of 6dEB utilizing three carbon sources,glucose, propionate and glycerol. Although propionate is presently most often used experimentally, our results indicated that glucose would be the most feasible substrate for 6dEB production from economic and long-term standpoints. Compared with Saccharomyces cerevisiae and Bacillus subtilis, E. coli was found to be a better heterologous host for the biosynthesis of 6dEB due to the higher MTMY value under the same conditions. Two strategies,including a flux distribution comparison analysis (FDCA)and linear minimization of metabolic adjustment based (LMOMA-based) methods, were proposed and employed for in silico strain improvement of 6dEB production, which yielded several potential gene targets for future experimental validation. In a further analysis, increasing the specific growth rate (SGR) or the non-growth associated maintenance (NGAM) was found to decrease the MTMY; while increasing the specific oxygen uptake rate (SOUR) or the specific carbon source uptake rate (SCUR) increased the MTMY. Taken together, our findings identified key factors directly affecting the MTMY of 6dEB production, which will guide future experimental research or even the industrial production of 6dEB.

High-throughput Screening Strategy Used for Enhanced Production of Pigment by Monascus purpureus D39-4

Jun Tan,Ju Chu,Wenjuan Shi,Cheng Lin,Yuanxin Guo,Ying-ping Zhuang,Siliang Zhang,Tadayuki Imanaka 한국식품과학회 2012 Food Science and Biotechnology Vol.21 No.6

Most of the fermentation experiment designs were limited by the low-throughput of shake flask, especially for the medium optimization. A simple high-throughput screening system was developed for the determination of pigment in Monascus purpureus fermentation samples. This downscaled system was designed to optimize medium composition combined with statistical methods. The total 29 experiments designed by the Box–Behnken were used to study the 4 most important operating variables on pigment production. The analysis revealed that the optimum concentrations of glucose, peptone, NaNO3, and KH2PO4were 51.42, 4.91, 1.00, and 1.00 g/L, respectively. A production of 69.5 U/mL was achieved in agreement with the prediction (68.9 U/mL) fermented in 24-deep-well microtiterplates. Furthermore, the fermentation medium optimized in the high-throughput system was verified in shake flasks, and the pigment production could be enhanced from 206.5 U/mL in un-optimized medium to 265.8 U/mL,giving nearly 1.30-fold increase in production.