Gastight box CR1601 (with clamp inside) The gastight box with a clamp inside (CR1601) enables microtiter plate fermentations requiring a specific gas-atmosphere (e.g. a higher CO2 concentration, or anearobic cultivations). The clamp system inside is identical to the clamp system for lowwell MTPs (see Lowwell plate covers and clamps), but this system can also harbour deepwell plates with sandwich covers. The gastight box can be mounted onto shaking platforms from Kuhner, or - after adding some extra holes in the shaker platform - on all other shaker types, and has been constructed to withstand continuous shaking up to 300 rpm at an amplitude of 25 mm, and 225 rpm at an amplitude of 50 mm. Because of these limitations in orbital shaking conditions, we advise to work either with 24 well MTPs and covers or with square half deepwell MTPs in combination with our universal covers for 96- well MTPs (CR 1596b) The gastight box has a gas inlet and a gas outlet (both via a ball-valve), that is compatible with standard 6 mm push-in connectors. The box is gastight (using an EPDM rubber sealing between the perspex box and the carbon groundplate), but is not resistant to overpressure or underpressure more than 0.1 bar. Therefore, the box can not be made anaerobic using vacuum cycles, but has to be flushed instead. The dimensions (groundplate 220x194 mm, total height including ball valves 220mm) allow the transfer in and out most anearobic chambers (via an airlock: vacuum cycles can be used provided the valves of the box are open, or the perspex box and the alu groundplate are transferred into the anaerobic chamber separately). Continuous flushing during shaking is feasible using PTFE tubing (outside diameter 6 mm). The total weight (including microtiter plates and covers) is approximately 2.5 kg, which implies that - also due to the relatively high heavy point - maximally 4-6 boxes can be fitted onto one shaking platform (depending on the shaker model). The gastight box can harbour either two deepwell MTPs with sandwich covers, or six lowwell MTPs with sandwich covers.
Controlling the gas atmosphere inside a shaker cabinet: With our regular clamp systems, the gas-atmosphere (CO 2 , O 2 concentration, etc), in which the plates + covers are incubated can be controlled by flushing the whole shaker cabinet with a certain gas mixture. Also, some shaker-cabinet models are equipped with an active humidity control. In the absence of an active humidity control, it is also possible - with most shaker models - to increase the humidity inside the shaker cabinet by closing its venting holes, and filling the water reservoir (if present), or simply by clamping an open Erlenmeyer flask half filled with water on the shaker platform. These simple measures will increase the relative humidity to 50-75 % in most cases. This is especially relevant in cold and dry climates (e.g. Scandinavia) where the humidity in labaratories in winter is often well below 50%. As a consequence, within shaker-incubators at 30-37 o C, the humity can easily drop below 25% (in the absence of the measures described above). Humidities below 50% may lead to unacceptable levels of evaporation from the wells (even when using our sandwich covers) and so must be avoided. Another way to control the gas-atmosphere (and/or increase the humidity) is to use: Our gastight boxes (CR1601, see below), which are equipped with a fully gastight EPDM seal and fully gastight valves
Clamp systems in boxes (to control the gas atmosphere)