Read by QxMD icon Read

fed batch

Seo-Young Park, Thomas M Reimonn, Cyrus Agarabi, Kurt Brorson, Seongkyu Yoon
Amino acids and glucose consumption, cell growth and monoclonal antibody (mAb) production in mammalian cell culture are key considerations during upstream process and particularly media optimization. Understanding the interrelations and the relevant cellular physiology will provide insight for setting strategy of robust and effective mAb production. The aim of this study was to further our understanding of nutrient consumption metabolism, since this could have significant impact on enhancing mAb titer, cell proliferation, designing feeding strategies, and development of feed media...
February 21, 2018: Biotechnology Progress
Sen Xu, Rubin Jiang, Roland Mueller, Nadja Hoesli, Thomas Kretz, John Bowers, Hao Chen
Lactate metabolism variations are frequently encountered in mammalian cell culture processes, especially during process scale-up. In this study, we took a multipronged approach to investigate the impact of pH, pCO2 , osmolality, base addition, and mixing conditions on the observed lactate variations in a Chinese Hamster Ovary (CHO) fed-batch process at 2,000 L scale. Two cultivating methods, CO2 -controlled and pH-controlled, were used to decouple the individual and synergistic effects from those factors. The individual effects from pH, pCO2 , and osmolality on lactate consumption/reproduction in the stationary phase were insignificant in the ranges studied though the initial lactate production rates varied...
February 21, 2018: Biotechnology Progress
Teresa Díaz, Sandy Fillet, Sonia Campoy, Raquel Vázquez, Javier Viña, José Murillo, José L Adrio
Improving the yield of carbohydrate to lipid conversion and lipid productivity are two critical goals to develop an economically feasible process to commercialize microbial oils. Lignocellulosic sugars are potential low-cost carbon sources for this process but their use is limited by the toxic compounds produced during biomass pretreatment at high solids loading, and by the pentose sugars (mainly xylose) which are not efficiently metabolized by many microorganisms. Adaptive laboratory evolution was used to select a Rhodosporidium toruloides strain with robust growth in non-detoxified wheat straw hydrolysates, produced at 20% solids loading, and better xylose consumption rate...
February 20, 2018: Applied Microbiology and Biotechnology
Yuanye Chen, Yongfei Liu, Dongqin Ding, Lina Cong, Dawei Zhang
L-tryptophan (L-trp) is a precursor of various bioactive components and has great pharmaceutical interest. However, due to the requirement of several precursors and complex regulation of the pathways involved, the development of an efficient L-trp production strain is challenging. In this study, Escherichia coli (E. coli) strain KW001 was designed to overexpress the L-trp operator sequences (trpEDCBA) and 3-deoxy-D-arabinoheptulosonate-7-phosphate synthase (aroGfbr ). To further improve the production of L-trp, pyruvate kinase (pykF) and the phosphotransferase system HPr (ptsH) were deleted after inactivation of repression (trpR) and attenuation (attenuator) to produce strain KW006...
February 20, 2018: Journal of Industrial Microbiology & Biotechnology
Tania Selas Castiñeiras, Steven G Williams, Antony Hitchcock, Jeffrey A Cole, Daniel C Smith, Tim W Overton
As high-level recombinant protein production (RPP) exerts a massive stress on the production host, an extensive literature on RPP optimization focuses on separating the growth phase from RPP production once sufficient biomass has been obtained. The aim of the current investigation was to optimize the benefits of the relatively neglected alternative strategy to achieve high-level RPP during growth by minimizing stress on the host. High yields of the biopharmaceutical recombinant human tumour necrosis factor alpha (rhTNFα) were obtained by fed-batch fermentation relevant to industrial production based upon parameters that most severely affected RPP in preliminary laboratory scale batch cultures...
February 14, 2018: Microbiology
Guillermo E Juarez, Estela M Galván
Klebsiella pneumoniae and Escherichia coli form mixed species biofilms in catheter-associated urinary tract infections. Recently, a detrimental effect of K. pneumoniae over E. coli was observed in mixed species biofilms grown in an artificial urine medium. The mechanism behind this competitive interaction was studied. K. pneumoniae partially outcompeted E. coli in early-stage batch-fed biofilms, whereas both microorganisms co-exist at longer times (K. pneumoniae:E. coli ratio, 55:1), as shown by cell counts and confocal microscopy...
February 19, 2018: Biofouling
Christopher R Vickery, Javier Cardenas, Marianne Bowman, Michael D Burkart, Nancy A Da Silva, Joseph P Noel
Polyketides are attractive compounds for uses ranging from biorenewable chemical precursors to high-value therapeutics. In many cases, synthesis in a heterologous host is required to produce these compounds in industrially relevant quantities. The type III polyketide synthase 2-pyrone synthase (2-PS) from Gerbera hybrida was used for the production of triacetic acid lactone (TAL) in Saccharomyces cerevisiae. Initial in vitro characterization of 2-PS led to the identification of active site variants with improved kinetic properties relative to wildtype...
February 19, 2018: Biotechnology and Bioengineering
Mariana Chesini, Evelyn Wagner, Diego J Baruque, Carolina E Vita, Sebastián F Cavalitto, Pablo D Ghiringhelli, Natalia L Rojas
Exoinulinases-enzymes extensively studied in recent decades because of their industrial applications-need to be produced in suitable quantities in order to meet production demands. We describe here the production of an acid-stable recombinant inulinase from Aspergillus kawachii in the Pichia pastoris system and the recombinant enzyme's biochemical characteristics and potential application to industrial processes. After an appropriate cloning strategy, this genetically engineered inulinase was successfully overproduced in fed-batch fermentations, reaching up to 840 U/ml after a 72-h cultivation...
February 15, 2018: Protein Expression and Purification
Zhiliang Yang, Zisheng Zhang
Background: 2,3-butanediol (2,3-BD) is a bulk platform chemical with various potential applications such as aviation fuel. 2,3-BD has three optical isomers: (2R, 3R)-, (2S, 3S)- and meso-2,3-BD. Optically pure 2,3-BD is a crucial precursor for the chiral synthesis and it can also be used as anti-freeze agent due to its low freezing point. 2,3-BD has been produced in both native and non-native hosts. Several pathogenic bacteria were reported to produce 2,3-BD in mixture of its optical isomers including Klebsiella pneumoniae and Klebsiella oxytoca ...
2018: Biotechnology for Biofuels
Amin Ramezani, Abbas Ghaderi
Targeted therapy using monoclonal antibodies (mAbs) against epidermal growth factor receptor-2 (ErbB2) has been utilized for the treatment of breast cancer, recently. Pertuzumab, one of the anti-ErbB2 mAbs, was approved by FDA in 2012 for the treatment of metastatic breast cancer. The aim of this study was to produce biosimilar version of pertuzumab in Chinese hamster ovary (CHO)-S cell line, and compare its ErbB2-binding and biological activities, with commercial drug, Perjeta. To this end, a dihydrofolate reductase (DHFR)-based strategy was used to produce a CHO-S stable cell pool capable of producing high levels of pertuzumab...
February 13, 2018: Monoclonal Antibodies in Immunodiagnosis and Immunotherapy
Jingjie Mo, Renzhe Jin, Qingrong Yan, Izabela Sokolowska, Michael J Lewis, Ping Hu
Glycation has been observed in antibody therapeutics manufactured by the fed-batch fermentation process. It not only increases the heterogeneity of antibodies, but also potentially affects product safety and efficacy. In this study, non-glycated and glycated fractions enriched from a monoclonal antibody (mAb1) as well as glucose-stressed mAb1 were characterized using a variety of biochemical, biophysical and biological assays to determine the effects of glycation on the structure and function of mAb1. Glycation was detected at multiple lysine residues and reduced the antigen binding activity of mAb1...
February 13, 2018: MAbs
Hemant J Purohit
Gut-microbiome provides the complementary metabolic potential to the human system. To understand the active participation and the performance of the microbial community in human health, the concept of gut as a plug-flow reactor with the fed-batch mode of operation can provide better insight. The concept suggests the virtual compartmentalized gut with sequential stratification of the microbial community in response to a typical host genotype. It also provides the analysis plan for gut microbiome; and its relevance in developing health management options under the identified clinical conditions...
March 2018: Indian Journal of Microbiology
Daniel Vázquez-Ramírez, Yvonne Genzel, Ingo Jordan, Volker Sandig, Udo Reichl
Increasing the yield and the productivity in cell culture-based vaccine manufacturing using high-cell-density (HCD) cultivations faces a number of challenges. For example, medium consumption should be low to obtain a very high concentration of viable host cells in an economical way but must be balanced against the requirement that accumulation of toxic metabolites and limitation of nutrients have to be avoided. HCD cultivations should also be optimized to avoid unwanted induction of apoptosis or autophagy during the early phase of virus infection...
February 9, 2018: Vaccine
Hong-Lei Zhang, Chao Zhang, Chao-Hong Pei, Meng-Nan Han, Zhi-Dong Xu, Cun-Hui Li, Wei Li
Trans-4-Hydroxy-L-proline (trans-Hyp) is a valuable chiral building block for the synthesis of pharmaceutical intermediates. Bioconversion of L-proline using recombinant strain with proline-4-hydroxylase (P4H) is a preferred biocatalytic process in the economical production of trans-Hyp. In the present study, a recombinant E. coli overexpressing hydroxylase (P4H), γ-glutamyl kinase and glutamate-semialdehyde dehydrogenase (ProBA) genes were constructed by knocking out the key genes in the metabolism. These key genes contained putA encoding proline dehydrogenase (PutA) in the L-proline metabolism and other catalytic enzyme genes, sucAB encoding α-ketoglutarate dehydrogenase (SucAB), aceAK encoding isocitratelyase (AceA) and isocitrate dehydrogenase kinase/phosphatase (AceK) in the TCA cycle...
February 12, 2018: Letters in Applied Microbiology
A Htun, T Sato, N Fukuma, M Hanada
This experiment was performed to investigate the effects of increases in passively acquired immunoglobulin G (IgG) by difructose anhydride (DFA) III supplementation on subsequent serum IgG concentration and health status in calves during the preweaning period. Thirty newborn female Holstein calves were paired by birth order, and 2 calves in each pair were fed 2 L of the same batch of colostrum within 2 h and at 10 h after birth, and followed by 2 L of the same batch of pooled colostrum at 20 h after birth. One calf from each pair was assigned to the control (n = 15) or treatment (n = 15) group...
February 7, 2018: Journal of Dairy Science
Jing Zhao, Maria Westerholm, Wei Qiao, Dongmin Yin, Shaojie Bi, Mengmeng Jiang, Renjie Dong
The present study investigates the conversion of acetate, propionate and hydrogen consumption linked to the microbial community structure and related to temperature and substrate concentration. Biogas reactors were continuously fed with coffee powder (20 g-COD/L) or acetate (20, 40, and 60 g-COD/L) and operated for 193 days at 37 °C or 55 °C conditions. Starting HRT was 23 days which was then reduced to 7 days. The kinetics of acetate and propionate degradation and hydrogen consumption rates were measured in batch assays...
February 2, 2018: Bioresource Technology
J M D Murray, E Hanna, P Hastie
Background: Nutritional supplements are frequently used by horse owners/caregivers to supplement their horse(s) diets. Some work has been done to identify the types of supplements fed and the reasons for doing so; however, this has been predominantly disciple-specific and with little focus on participants' perceptions of supplement testing and regulation. The aim of this study was to gain an insight into the use and perceptions of equine dietary supplements in the Irish equestrian industry...
2018: Irish Veterinary Journal
Zhi-Hua Liu, Shangxian Xie, Furong Lin, Mingjie Jin, Joshua S Yuan
Background: Lignin valorization has recently been considered to be an essential process for sustainable and cost-effective biorefineries. Lignin represents a potential new feedstock for value-added products. Oleaginous bacteria such as Rhodococcus opacus can produce intracellular lipids from biodegradation of aromatic substrates. These lipids can be used for biofuel production, which can potentially replace petroleum-derived chemicals. However, the low reactivity of lignin produced from pretreatment and the underdeveloped fermentation technology hindered lignin bioconversion to lipids...
2018: Biotechnology for Biofuels
Emmanuel Manirafasha, Theophile Murwanashyaka, Theoneste Ndikubwimana, Nur Rashid Ahmed, Jingyi Liu, Yinghua Lu, Xianhai Zeng, Xueping Ling, Keju Jing
Arthrospira (Spirulina) platensis is known to have high-quality proteins content and phycocyanin as one of the major pigment constituents of the cells, and the most challenging problem associated with phycocyanin production in Arthrospira is to optimize its intracellular accumulation. The present study evaluated the metabolic stress conditions (by nutrient enrichment) of Arthrospira platensis FACHB-314 for boosting biomass growth and high content phycocyanin accumulation. Experimental results showed that 5 mM sodium glutamate and 7...
December 23, 2017: Bioresource Technology
Lu Liu, Junhui Chen, Phaik-Eem Lim, Dong Wei
The single cell oil (SCO) production by the mono and mixed culture of microalgae Chlorella pyrenoidosa and red yeast Rhodotorula glutinis was investigated using non-detoxified cassava bagasse hydrolysate (CBH) as carbon source. The results suggested that the two strains were able to tolerate and even degrade some byproducts presented in the CBH, and the mixed culture approach enhanced the degradation of certain byproducts. Biomass (20.37 ± 0.38 g/L) and lipid yield (10.42 ± 1.21 g/L) of the mixed culture achieved in the batch culture were significantly higher than that of the mono-cultures (p < 0...
February 2, 2018: Bioresource Technology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"