Therefore, the chromium content of tanned leather sample serves
as an indirect index of degree of fibre opening up. The percentage of
chromium content as Cr
2
O
both conventional and experimental
leather given in Table 6. Enzyme treated leather showed a marginal
increase in chromium uptake as compared to conventionally processed
leather, indicating the advantage of enzyme based process.
The increased chromium uptake in the tanning process is very
much reflected in the physical properties. Additionally, the enzymatic
fibre opening assists in bringing down the level of chromium
discharged in the effluent, adding another environmental benefit.
Discharge of unreacted chromium (III) and its exposure to alkaline
pH, in the presence of calcium hydroxide may trigger the formation
of toxic Cr
6þ
3
. Therefore the enzymatic process in leather processing
is advantageous in several ways.