The conventional unhairing process in leather making utilises large amount of lime and sodium sulphide which is hazardous and poses serious waste disposal concerns. Under acidic conditions, sodium sulphide liberates significant quantities of hydrogen sulphide which causes frequent fatal accidents. Further, the conventional unhairing process involves destruction of the hair leading to increased levels of biological oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS) and total suspended solids (TSS) in the effluent. A safe approach is needed to overcome such environmental and health problems through an eco-benign process. The present study deals with a clean technology in which the keratinous body is detached from the dermis using enzymes produced from Bacillus crolab MTCC 5468 by solid state fermentation (SSF) as an alternative to noxious chemicals. Complete unhairing of skin could be achieved with an enzyme concentration of 1.2 % (w/w). The bio-chemical parameters of the spent liquor of the enzymatic process were environmentally favourable when compared with conventional method. The study indicates that the enzymatic unhairing is a safe process which could be used effectively in leather processing to alleviate pollution and health problems.
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http://dx.doi.org/10.1007/s11356-016-7645-6 | DOI Listing |
Heliyon
July 2024
Manufacturing Industry Development Institute, Leather and Leather Products Industry Research and Development Center, P.O. Box 24692 Code 1000, Addis Ababa, Ethiopia.
Hair burning unhairing and dampening of tannery wastes during the hair-saving unhairing process are becoming significant problems in the tanning industry. Therefore, this research article focuses on the extraction of keratin hydrolysate (KH) and its application as a chrome exhaust aid and keratin filler in leather manufacturing process. The structure, morphology and functional groups of the extract were examined using X-Ray Diffractometer (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectrometer (FTIR), respectively.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
April 2022
Faculty of Petroleum and Chemical Engineering, Razi University, Kermanshah, Iran.
The effluent generated by Merox unit of oil refinery was used instead of freshwater for bovine hide unhairing because of its proper composition and alkalinity. The effect of temperature, treatment period, sodium sulfide (NaS), and calcium carbonate (CaCO) dosage was investigated on unhairing efficiency using lutrom (unhairing slurry) prepared from the Merox effluent (effluent-based lutrom). Under similar operating conditions and chemicals' dosage, the effluent-based lutrom resulted in a higher efficiency (98.
View Article and Find Full Text PDFInt J Biol Macromol
February 2019
Laboratory of Microbial Biotechnology and Engineering Enzymes (LMBEE), Centre of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour Km 6, P.O. Box 1177, Sfax 3018, Tunisia. Electronic address:
The current paper reports the purification and biochemical characterization of two extracellular keratinolytic enzymes, with moderate elastolytic activity, from Bacillus amyloliquefaciens strain S13 newly isolated from the brown alga Zonaria tournefortii. The enzymes were purified to homogeneity by precipitation with (NH)SO-dialysis, followed by size exclusion HPLC column, and submitted to biochemical characterization assays. The findings revealed that the pure enzymes designated KERZT-A and B were monomers with molecular masses of 28 and 47 kDa, respectively.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
January 2018
Leather Process Technology Department, Central Leather Research Institute, Adyar, Chennai, 600 020, India.
Usage of the animal fleshing waste as the source of carbon and nitrogen for animal skin unhairing protease (EC 3.4.21) production along with agro-industrial wastes like wheat bran has been investigated.
View Article and Find Full Text PDFAppl Biochem Biotechnol
June 2017
Leather Process Technology Department, Central Leather Research Institute, Adyar, Chennai, 600020, India.
Enzyme-based unhairing in replacement of conventional lime sulfide system has been attempted as an alternative for tackling pollution. The exorbitant cost of enzyme and the need for stringent process control need to be addressed yet. This study developed a mechanism for regulated release of protease from cheaper agro-wastes, which overcomes the necessity for stringent process control along with total cost reduction.
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