Reducing Water Usage in Bio-processing

Fermentation and cell-culture processes are extremely water-intensive. They may require over 10,000L of water for every kilogram of product. Furthermore the majority of this water must be highly purified. This presentation describes the results of a series of simulation studies aimed at evaluating the effect of process design options on water consumption. In a typical stainless steel cell-culture process, equipment clean-in-place (CIP) is the largest consumer accounting for over 60% of the total water usage. Single-use bio-reactor systems and vessels eliminate much of the CIP water requirement and represent the single most effective means of water reduction. There are, however practical and economic limits to their application. In cases where fixed equipment is unavoidable, some process design considerations can reduce consumption. In general, water reduction designs favor larger batchsizes and fewer cycles. Cell-culture optimization can reduce water by reducing bio-reactor size requirements although this will have little effect on the downstream water consumption. In-line buffer dilution can reduce the size requirements and therefore the amount cleaning water for buffer prep tanks.Single-use chromatography systems can reduce water consumption by eliminating column preprocessing and storage operations. Operational improvements and good clean and dirty hold management can further reduce water consumption.