The cellular material is also dried using a drum dryer, and the ethyl acetate from both the SL stream (from the evaporator and vacuum dryer) and the cellular stream is recovered, passed through a molecular sieve dehydration unit and recycled for subsequent use. By recycling the ethyl acetate, cost-intensive processes such as higher solvent requirements and solvent disposal costs are avoided,helping to reduce overall production costs. Typically,smaller scale production processes use a final hexane precipitation step to further purify the SL products.In this model, the hexane step has been omitted due to the additional solvent handling problems associated with a costly,highly flammable solvent. Experience has shown that,although the SLs may not be as pure as when hexane is used, in the absence of water the simple concentration of the SLs from ethyl acetate will cause crystallization to occur, thus eliminating the need for hexane during industrial-scaleproduction.