A two-stage heat treatment process is provided to improve the processability of recombinant microbial biomass comprising an enzyme having perhydrolytic activity. More specifically, a process is provided to treat the recombinant microbial biomass comprising a Thermotoga sp. acetyl xylan esterase having perhydrolytic activity such that microfiltration may be used to partially-purify and/or concentrate protein preparations. The acetyl xylan esterase may be used to produce peroxycarboxylic acids suitable for use in a variety of applications such as cleaning, disinfecting, sanitizing, bleaching, wood pulp processing, and paper pulp processing applications.