2.10. Scanning electron microscopic evaluation
Skin samples of both experimental and conventional trials were
cut and stored in a deep freezer (70
C) for 24 h, and thereafter
lyophilised. The freeze dried samples were gold coated and the
surface morphology was observed using ASOEL JSM 5300 scanning
electron microscope.
2.11. Histological studies
In order to evaluate the effect of galactosidase in fibre opening of
the skin matrix, histological studies were carried out. The samples
of both experimental and conventional trials were fixed using
formalin (10%) in PBS, cassetted and blocked in paraffin wax.
Sample sections of 4e5
mm thickness were cut using microtome
(Leica) and mounted on glass slide. The tissue specimens thus obtained
were dehydrated using series of alcohol (30%, 60% and 100%)
and stained using haematoxylin and eosin and visualized in bright
field microscope, to assess the extent of fibre opening and collagen
distribution in the sample.
2.12. Estimation of chromium content
Subsequent to fibre opening, the skin samples were tanned
using chromium salts. Chromium content of leathers was determined
by the official procedure (IUP 2, 2000).
2.13. Evaluation of strength characteristics and visual assessment of
leathers
Various physical properties such as tensile strength, percentage
elongation at break, tear strength and grain crack strength of
experimental and conventional processes leather samples were
examined as per the standard procedure (IUP 6, 2000).
2.14. Analysis of composite waste liquor
Spent liquor from both conventional and experimental processes
collected at various stages and analyzed pollution parameters
such as Chemical Oxygen Demand (COD) and Total Dissolved
Solids (TDS) according to the method followed by Thangam et al.
(2001). The results are expressed in parts per million (ppm).