Chrome tanning is a versatile tanning system, but the pollution problems of chromium due to inadequacy of treatment systems and possible formation of Cr(VI), a carcinogen, have led to search for an ecofriendly and viable alternative tanning system. The present investigation focuses on the development of a novel, high performance and thermally stable aldehyde tannage system to produce chrome free leather by cross linking the NH 2 groups of collagen with glutaraldehyde (CHO-CH 2 -CH 2 -CH 2 -CHO). After as usual soaking, liming, deliming, bating and pickling operations the pickle pelts were tanned with glutaraldehyde and other syntans. This developed chrome free tanning process produce crust leathers exhibiting thermal stability >85 O C and reducing the TDS value with 0% emission of Cr-salt in tannery discharge.

Leather tanning industry, considered one of the polluting industries, poses various environmental threats to its every sphere. It produces various types of solid wastes as well as liquid wastes. Among the solid wastes, untanned raw trimmings contribute for about 5-7% of the total quantity of raw materials processed. If suitably utilized, these by-products of tanning industry could be a useful resource for various applications. This research work deals with utilization of raw trimmings of tannery solid waste to protein hydrolysate by acetic acid with varying acid concentration, acid solution, temperature and time. The maximum about 76% protein hydrolysate was obtained at 1.5M acid concentration and 80ºC.

The present investigation was conducted to analyze the activity of enzymes (protease, αamylase, cellulase and urease) of selected salad vegetables (white radish, red radish, beet, carrot, papaya, cucumber and tomato) as well as to determine the effect of chemical agents and metallic salts on the stability of enzymes. Salad vegetables are one of the cheap sources of adequate vitamins, minerals and enzymes. The protease, α-amylase and cellulase activity were highest in papaya (4.11±0.21 U/g, 1.68±0.21 U/g and 0.26±0.13 U/ g) whereas the urease activity was not detected in papaya, cucumber and tomato. The protease, α-amylase and cellulase activity of papaya were increased 24.83%, 42.26% and 57.69% than cucumber while the cellulase activity of carrot was increased 44.45% than tomato. The activity of protease and α-amylase of beet were decreased 52.44%, 33.63% while the cellulase activity of beet was increased 36.36% from radish. The toxicity indicating urease enzyme activity was not detected in papaya, tomato and cucumber but negligible in radish, beet and carrot which can be nullified. The activities of enzymes were increased in the presence of metallic salts such as Ca2+, Mg2+ and Mn2+ while Fe2+, Zn2+ and Cu2+ inhibited the enzyme's activity moderately. Results revealed that in the presence of higher concentrations of urea, EDTA and acetic acid, the activities of all the enzymes were completely inhibited.

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