title: Cleaner processing: a sulphide-free approach for depilation of skins.
abstract: 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.
authors.affiliation: Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi, 110 001, India.
authors.forename: Ammasi
authors.initials: A
authors.lastname: Ranjithkumar
authors.affiliation: Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi, 110 001, India.
authors.forename: Jayanthi
authors.initials: J
authors.lastname: Durga
authors.affiliation: Leather Processing Division, CSIR-Central Leather Research Institute, Adyar, Chennai, 600020, India.
authors.forename: Ramakrishnan
authors.initials: R
authors.lastname: Ramesh
authors.affiliation: Department of Biotechnology, CSIR-Central Leather Research Institute, Adyar, Chennai, 600020, India. rose@clri.res.in.
authors.forename: Chellan
authors.initials: C
authors.lastname: Rose
authors.affiliation: Leather Processing Division, CSIR-Central Leather Research Institute, Adyar, Chennai, 600020, India. cmurali62@yahoo.com.
authors.forename: Chellappa
authors.initials: C
authors.lastname: Muralidharan
mesh_terms: D001407:Bacillus / Q000201:enzymology; D017610:Calcium Compounds; D004787:Environmental Pollution / Q000517:prevention & control; D006197:Hair; D006862:Hydrogen Sulfide; D007633:Keratins; D010087:Oxides; D012867:Skin; D013440:Sulfides; D013633:Tanning; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D017610:Calcium Compounds; D010087:Oxides; D013440:Sulfides; D007633:Keratins; C016538:lime; C033479:sodium sulfide; D006862:Hydrogen Sulfide
keywords: Alkaline protease; Eco-benign process; Enzymatic unhairing; Health; Process liquor; Safety