Enzymatic Hydrolysis of Chromium Tanned Leather Wastes, Amino Acid Composition Analysis and Chemical Characterization of Hydrolysate
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Date
2020Author
Andanyi, Humphrey L
Type
ThesisLanguage
enMetadata
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The disposal of leather wastes poses many challenges and is a major threat to the environment in many
countries across the world. Large amounts of wastes from the tanneries including: shavings, trimmings,
sludge and untreated waste waters are disposed to the environment and pose a threat to the environment
and humans. Solid wastes in particular are non-biodegradable and therefore remain in the environment
for a long period of time. The major tanning agent is chromium, a clear indication that the solid wastes
and even the liquid waste expose the environment to significant amount of chromium.
In this study enzymes extracted from Lake Bogoria, an extremophile environment were used to hydrolyze
leather trimmings to generate valuable products and consequently reduce the effect of solid waste disposal
and chromium discharged to the environment. Different parameters such as pH, temperature and time
were optimized for enzymatic hydrolysis. Characterization of the hydrolysate was done using FTIR and
HPLC and the heavy metals were analyzed using Inductively Coupled Plasma mass spectroscopy (ICPMS).
The enzyme was able to hydrolyze the trimmings under optimum conditions. The optimum conditions for
hydrolysis were pH of 12 and a temperature of 75oC. FTIR analysis of the samples showed peaks at
3290.56 cm -1 and 3334.92 cm -1 indicating the presence of amide bands. The HPLC analysis indicated
the presence of 16 and 15 amino acids in the freeze dried and dry filtrate respectively. Further, glycine
was the most abundant amino acid comprising 37.83% and 43.36% mole fraction in the freeze dried and
dry filtrate samples respectively. Glycine also indicated large percentage by mass in both samples, 25.17%
in freeze dried sample and 29.23% by weight in the dry filtrate. Both Histidine and Tryptophan were
absent in both samples. The element content of the samples was analyzed using Inductively Coupled
Plasma mass spectroscopy (ICP-MS) and it indicated the presence of Cr and S, in addition to several other
elements. The dry filtrate showed higher element content filtrate than in the freeze dried samples. This
study shows that gelatin can be obtained from the leather wastes and the enzyme hydrolysis process can
be achieved within 21 hours, under the optimum conditions established.
Publisher
University of Nairobi
Rights
Attribution-NonCommercial-NoDerivs 3.0 United StatesUsage Rights
http://creativecommons.org/licenses/by-nc-nd/3.0/us/Collections
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