Bacillus sp. CFR1601, isolated from decaying plant litter, produced an extra-cellular endo-mannanase (198.0 IU/g)
under solid state fermentation (SSF) using defatted coconut residue as the prime solid substrate. In order to
enhance endo-mannanase production, three component, five level central composite design (CCD) of response
surface methodology (RSM) was used. Based on contour plots and variance analysis, optimum conditions for endomannanase
production from Bacillus sp. CFR1601 were attained when defatted coconut residue was supplemented
with sesame oil meal (10.0, w/w), Tween-80 (0.2%, v/v) and inoculated with bacterial cells from log phase (12h
old; OD600nm ≈ 3.6). The empirical model developed through RSM brought about 4.04–4.39-fold (800.0–870.0 IU/g)
improvement in endo-mannanase yield as compared to un-optimized growth conditions. Downstream processing
of endo-mannanase from SSF media was carried out for the first time using polyethylene glycol (PEG)/salt aqueous
two phase system (ATPS). ATPS system consisting of a combination of PEG 3350 12.0% (w/w), Na2SO4 12.0% (w/w),
protein load 10.0% (w/w) and pH 5.0 resulted in one-sided partitioning of endo-mannanase towards bottom phase
with 3.8-fold purification and 95.4% recovery. Second stage ATPS with fresh top phase further improved purification
of endo-mannanase to 12.32-fold. Our overall results suggest a cost-effective and integrated process for production
and downstream processing of endo-mannanase.