负担得起且易于获得的小规模生物反应器将对研究界具有重大益处。在以前的工作中,一个开源的,自动化生物反应器系统被设计为操作高达30毫升规模与在线光学监测,搅拌,和温度控制,这个系统,被称为Chi。Bio,现在可在商业上获得,其成本通常比商业生物反应器低1-2个数量级。在这项工作中,我们进一步扩大了Chi的能力。生物系统通过硬件和软件修改实现连续pH监测和控制。对于硬件修改,我们采购低成本,商业pH电路,并对Chi进行了直接修改。生物头板,以实现连续pH监测。对于软件集成,我们引入了Chi内部测量的pH值的闭环反馈控制。生物反应器,并将pH控制模块集成到现有的Chi中。生物用户界面。我们证明了通过合成聚酯的小规模解聚来控制pH值的实用性,聚对苯二甲酸乙二醇酯(PET),使用基准角质酶,并将其与250mL生物反应器水解反应进行比较。在PET转化率和速率方面的结果,通过碱添加和产品释放曲线测量,在统计上是等同的,与Chi。相对于250mL生物反应器设置,允许所需的纯化酶减少20倍的生物系统。通过廉价的修改,在Chi中进行pH控制的能力。生物反应器拓宽了该系统中生化反应和生物培养的潜在研究范围,并且还可以适用于其他生物反应器平台。
Small-scale bioreactors that are affordable and accessible would be of major benefit to the research community. In previous work, an open-source, automated bioreactor system was designed to operate up to the 30 mL scale with online optical monitoring, stirring, and temperature control, and this system, dubbed Chi.Bio, is now commercially available at a cost that is typically 1-2 orders of magnitude less than commercial bioreactors. In this work, we further expand the capabilities of the Chi.Bio system by enabling continuous pH monitoring and control through hardware and software modifications. For hardware modifications, we sourced low-cost, commercial pH circuits and made straightforward modifications to the Chi.Bio head plate to enable continuous pH monitoring. For software integration, we introduced closed-loop feedback control of the pH measured inside the Chi.Bio reactors and integrated a pH-control module into the existing Chi.Bio user interface. We demonstrated the utility of pH control through the small-scale depolymerization of the synthetic polyester, poly(ethylene terephthalate) (PET), using a benchmark cutinase enzyme, and compared this to 250 mL bioreactor hydrolysis reactions. The results in terms of PET conversion and rate, measured both by base addition and product release profiles, are statistically equivalent, with the Chi.Bio system allowing for a 20-fold reduction of purified enzyme required relative to the 250 mL bioreactor setup. Through inexpensive modifications, the ability to conduct pH control in Chi.Bio reactors widens the potential slate of biochemical reactions and biological cultivations for study in this system, and may also be adapted for use in other bioreactor platforms.