Media photo‐degradation in pharmaceutical biotechnology – impact of ambient light on media quality,cell physiology,and IgG production in CHO cultures

BACKGROUND

Many vital components in bioprocess media are prone to photo‐conversion or photo‐degradation upon exposure to ambient light, with severe negative consequences for biomass yield and overall productivity. However, there is only limited awareness of light irradiation as a potential risk factor when working in transparent glass bioreactors, storage vessels or disposable bag systems. The chemical complexity of most media renders a root‐cause analysis difficult. This study investigated in a novel, holistic approach how light‐induced changes in media composition relate to alterations in radical burden, cell physiology, morphology, and product formation in industrial Chinese hamster ovary (CHO) bioprocesses.

RESULTS

Two media formulations from proprietary and commercial sources were tested in a pre‐hoc light exposure scenario prior to cultivation. Using fluorescence excitation/emission (EEM) matrix spectroscopy, a photo‐sensitization of riboflavin was identified as a likely cause for drastically decreased IgG titers (up to ?80%) and specific growth rates (?50% to ?90%). Up to three‐fold higher radical levels were observed in photo‐degraded medium. On the biological side, this resulted in significant changes in cell morphology and aberrations in the normal IgG biosynthesis/secretion pathway.

CONCLUSION

These findings clearly illustrate the underrated impact of room light after only short periods of exposure, occurring accidentally or knowingly during bioprocess development and scale‐ up. The detrimental effects, which may share a common mechanistic cause at the molecular level, correlate well with changes in spectroscopic properties. This offers new perspectives for online monitoring concepts, and improved detectability of such effects in future. © 2018 The Authors. Journal of Chemical Technology & Biotechnology published by JohnWiley & Sons Ltd on behalf of Society of Chemical Industry.

     

基于消耗碳氮比进行底物分配和油脂得率预测

微生物油脂作为胞内代谢产物,其脂肪酸组成和植物油类似,是生物柴油和油脂工业理想替代原料。为了进一步了解底物中碳氮比对油脂合成的影响,通过恒化培养的方法,研究了圆红冬孢酵母在不同稀释率条件下,消耗碳氮比和底物在油脂和非油生物量之间的分配以及和油脂得率之间的关系。通过碳、氢、氧和氮的化学反应计量学分析,并根据不同稀释率稳态时所消耗C/N比,构建了底物碳在油脂和非油生物量之间的分配模型。利用实验数据确定了模型参数:最大油脂碳得率Y_L^max为0.51 mol C·(mol C)^-1,最大菌体碳得率Y_L^max为0.52 mol C·(mol C)^-1,促使油脂合成的临界C/N比为12.1 mol C·(mol C)^-1。利用该分配模型预测不同消耗C/N比的油脂得率,预测值为实验值的 95.2%～116.7%,表明模型可靠性较好。     

A systems engineering perspective on process integration in industrial biotechnology

Biotechnology has many applications in health care, agriculture, industry and the environment. By using renewable raw materials, biotechnology contributes to lowering greenhouse gas emissions and moving away from a petro‐based towards a circular sustainable economy. However, major developments are still needed to make industrial biotechnology an economic alternative to conventional processes for fuels, specialty and/or bulk chemicals production. Process integration is a holistic approach to process design, which emphasizes the unity of the process and considers the interactions between different unit operations from the outset, rather than optimizing them separately. Furthermore, it also involves the substitution of two or more unit operations by one single novel unit capable of achieving the same process goal. Conversely, process systems engineering (PSE) deals with the analysis, design, optimization, operation and control of complex process systems, as well as the development of model‐based methods and tools that allow the systematic development of processes and products across a wide range of systems involving physical and chemical change. Mature tools and applications are available for chemical technology and steps have been taken to apply PSE principles also to bioprocess technology. This perspective paper argues that an interdisciplinary approach is needed towards integrated bio‐processing in order to link basic developments in biosciences with possible industrial applications. PSE can foster the application of existing and the development of new methods and tools for bioprocess integration that could promote the sustainable production of bio‐/chemical products. The inclusion of PSE principles and methods in biochemical engineering curricula and research is essential to achieve such goals. © 2014 Society of Chemical Industry     

温岭观岙污水厂一期工艺诊断及二期扩建方案研究

温岭市观岙污水处理厂现有一期工程的规模为7×104 m3/d,采用氧化沟工艺,出水水质执行国家二级排放标准.通过系统化的工艺诊断发现,一期工艺的脱氮除磷效果不甚理想,出水NH3-N、TN和TP浓度不能稳定达到未来的一级B标准要求.因此,建议修理或更换表曝机及相关主要设备、调整工艺运行参数、改造成MO工艺、增加化学除磷单元.同时,对二期扩建工程的生物智能控制系统进行了研究,从合理的管路布置和管径大小、精确的在线仪表、优良的鼓风供气系统三方面提出了功能实现要求,以期达到生物工艺过程控制和节能减排.     

Online monitoring of a bioprocess based on a multi‐analyser system and multivariate statistical process modelling

Multivariate statistical process control (MSPC) was for the first time applied to analyse data from a bioprocess on‐line multi‐analyser system consisting of an electronic nose (EN), a near‐infrared spectroscope (NIRS), a mass spectrometer (MS) and standard bioreactor probes. One hundred and fifty sensor signals from the electronic nose, 1050 wavelength signals from the NIRS, carbon dioxide evolution rate calculated from mass spectrometer signals and standard bioreactor data (eg amount of substrate fed) were interrogated for their ability to model a bioprocess using MSPC. The models obtained were validated on a recombinant Escherichia coli fed‐batch process for tryptophan production. Limiting trajectories were defined in the MSPC models for warning, action, and process experience with respect to biomass and tryptophan concentrations. The results showed the capacity and robustness of MSPC models for monitoring with multi‐analysers and allowed a comparison of the different analysers' suitability for this kind of data processing. Furthermore, the results demonstrate that MSPC models provide a functional and versatile framework for coping with large information flows and are also suited to a variety of other bioprocessing monitoring and control tasks. © 2002 Society of Chemical Industry     

Bipolar membrane electrodialysis for clean production of L-10-camphorsulfonic acid: From laboratory to industrialization

In this study, bipolar membrane electrodialysis (BMED) was implemented for cleaner production of L-10-camphorsulfonic acid (L-CSA) to lower the environmental impact. Under the current density of 300–400 A/m² and feed salt concentration of 6–10 wt.%, the energy consumption and current efficiency were 2.24–2.70 kWh/kg and 20.89–29.5%, respectively. Positron annihilation lifetime spectroscopy, x-ray photoelectron spectroscopy with ion beam etching, and other characterizations were used to elucidate the transport behaviors of large-sized anions across the membranes. It was speculated that the large-sized camphor sulfonate ions were more likely to deposit on the surface of the anion-exchange membrane to form a deposition layer under a direct current electric field. The appearance of water splitting at this deposition layer would offset the water dissociation in the bipolar membrane. Nevertheless, the successful commissioning of industrial-scale stack proved the feasibility and sustainability of BMED technique for a closed loop L-CSA production.     

Feammox： 一种新型自养生物脱氮技术

厌氧氨氧化耦合Fe(Ⅲ)还原,即铁氨氧化（Feammox）技术,是近年来新发现的一种以廉价、易得的铁作为微生物电子供体的新型自养生物脱氮技术。该技术具有无需有机碳源、成本低、污泥产量低、不产生温室气体等显著优点,是自然系统和污水处理系统等领域潜在的脱氮途径。本文聚焦于Feammox的产生和发展,详细介绍了该技术的作用机制及其参与反应的主要微生物特征,认为Feammox过程中起主要作用的微生物是一类能驱动氨氧化的铁还原菌;简要分析了pH、温度、溶解氧、有机物及铁源等影响因素;探讨了与FeNiR、Anammox和反硝化等氮损失途径的关系。最后,提出了Feammox仍面临的挑战,展望了未来发展趋势,指出菌的快速富集和分离纯化、控制参数以及与其他脱氮途径之间的相互作用是Feammox未来的研究方向。