Goldrick Stephen, Lovett David, Montague Gary, Lennox Barry
Biopharmaceutical Bioprocess Technology Centre, Merz Court, Newcastle University, Newcastle-upon-Tyne NE1 7RU, UK.
Perceptive Engineering Limited, Vanguard House, Keckwick Lane, Daresbury, Cheshire WA4 4AB, UK.
Bioengineering (Basel). 2018 Sep 25;5(4):79. doi: 10.3390/bioengineering5040079.
Raman spectroscopy is a novel tool used in the on-line monitoring and control of bioprocesses, offering both quantitative and qualitative determination of key process variables through spectroscopic analysis. However, the wide-spread application of Raman spectroscopy analysers to industrial fermentation processes has been hindered by problems related to the high background fluorescence signal associated with the analysis of biological samples. To address this issue, we investigated the influence of fluorescence on the spectra collected from two Raman spectroscopic devices with different wavelengths and detectors in the analysis of the critical process parameters (CPPs) and critical quality attributes (CQAs) of a fungal fermentation process. The spectra collected using a Raman analyser with the shorter wavelength (903 nm) and a charged coupled device detector (CCD) was corrupted by high fluorescence and was therefore unusable in the prediction of these CPPs and CQAs. In contrast, the spectra collected using a Raman analyser with the longer wavelength (993 nm) and an indium gallium arsenide (InGaAs) detector was only moderately affected by fluorescence and enabled the generation of accurate estimates of the fermentation's critical variables. This novel work is the first direct comparison of two different Raman spectroscopy probes on the same process highlighting the significant detrimental effect caused by high fluorescence on spectra recorded throughout fermentation runs. Furthermore, this paper demonstrates the importance of correctly selecting both the incident wavelength and detector material type of the Raman spectroscopy devices to ensure corrupting fluorescence is minimised during bioprocess monitoring applications.
拉曼光谱是一种用于生物过程在线监测和控制的新型工具，通过光谱分析可对关键过程变量进行定量和定性测定。然而，拉曼光谱分析仪在工业发酵过程中的广泛应用受到与生物样品分析相关的高背景荧光信号问题的阻碍。为解决这一问题，我们研究了荧光对从两种具有不同波长和探测器的拉曼光谱设备收集的光谱的影响，这两种设备用于分析真菌发酵过程的关键过程参数（CPPs）和关键质量属性（CQAs）。使用波长较短（903 nm）的拉曼分析仪和电荷耦合器件探测器（CCD）收集的光谱被高荧光干扰，因此无法用于预测这些CPPs和CQAs。相比之下，使用波长较长（993 nm）的拉曼分析仪和砷化铟镓（InGaAs）探测器收集的光谱仅受到适度的荧光影响，并能够生成发酵关键变量的准确估计值。这项新工作首次在同一过程中对两种不同的拉曼光谱探头进行了直接比较，突出了高荧光对整个发酵过程中记录的光谱造成的重大不利影响。此外，本文证明了在生物过程监测应用中正确选择拉曼光谱设备的入射波长和探测器材料类型以确保将干扰荧光降至最低的重要性。
