Integrated hair removal and fiber opening process using mixed enzymes
Tóm tắt
The use of enzyme-based products for many areas in leather making has been projected and some have found their way in commercial practices. Proteolytic and α-amylase enzymes are used in hair removal and fiber opening, respectively, producing comparable results to conventional practice of lime and sulfide-based dehairing and fiber opening. However, this process is a two-step sequence in which dehairing is performed by the proteolytic enzyme followed by fiber opening through α-amylase. In this study, an attempt has been made to achieve a single-step dehairing and fiber opening using mixed enzymes. A commercial product containing a mixture of α-amylase and protease is used for simultaneous dehairing and fiber opening of goatskins. Standardized experiments show that the leathers obtained were comparable to that of the conventionally produced leathers in terms of all the physical and bulk properties. The input–output analysis validates the observations made for dehairing and fiber opening in the preliminary trials, which are also confirmed through scanning electron micrographs. Reductions in water consumption, wastewater discharge, COD and TS loads are in the order of 30% when compared to conventional leather processing. There seems to be a significant reduction in the expenditure incurred on the leather processing upon introducing the integrated enzymatic beamhouse process.
Tài liệu tham khảo
Aravindhan R, Saravanabhavan S, Thanikaivelan P, Rao JR, Chandrasekaran B, Nair BU (2004) A biodriven lime and pickle free tanning paves way for greener garment leather production. J Am Leather Chem Assoc 99:53
Clesceri LS, Greenberg AE, Trussell RR (1989) Standard methods for the estimation of water and wastewater, 17th edn. American Public Health Association, Washington
Germann HP (1999) The ecology of leather production—present state and development trends. In: Proceedings of the XXV IULTCS congress. Tata McGraw-Hill, New Delhi
IUP 2 (International Commission of Physical Testing) (2000) Sampling. J Soc Leather Technol Chem 84:303
IUP 36 (International Commission of Physical Testing) (2000) Measurement of leather softness. J Soc Leather Technol Chem 84:377
IUP 6 (International Commission of Physical Testing) (2000) Measurement of tensile strength and percentage elongation. J Soc Leather Technol Chem 84:317
IUP 8 (International Commission of Physical Testing) (2000) Measurement of tear load—double edge tear. J Soc Leather Technol Chem 84:327
Maia RAM (1998) Clean technologies, targets already achieved and trends for coming years. J Soc Leather Technol Chem 82:111
Saravanabhavan S, Aravindhan R, Thanikaivelan P, Rao JR, Nair BU (2003) Green solution for tannery pollution: effect of enzyme based lime-free unhairing and fiber opening in combination with pickle-free chrome tanning. Green Chem 5:707
Shrewsbury C (2002) Biotechnology for improved product quality. World Leather February:40
SLP 9 (SLTC Commission for Physical Testing) (IUP 9) (1996) Measurement of distension and strength of grain by the ball burst test. Official methods of analysis. The Society of Leather Technologists and Chemists, Northampton
Thanikaivelan P, Rao JR, Nair BU, Ramasami T (2002) Zero discharge tanning: a shift from chemical to biocatalytic leather processing. Environ Sci Technol 36:4187
Thanikaivelan P, Rao JR, Nair BU, Ramasami T (2003) Approach towards zero discharge tanning: role of concentration on the development of ecofriendly liming–reliming processes. J Clean Prod 11:79
Thanikaivelan P, Rao JR, Nair BU, Ramasami T (2004a) Ecofriendly bio-process for leather processing. US Patent 6,708,531
Thanikaivelan P, Rao JR, Nair BU, Ramasami T (2004b) Progress and recent trends in biotechnological methods for leather processing. Trends Biotechnol 22:181
Thanikaivelan P, Rao JR, Nair BU, Ramasami T (2005a) Recent trends in leather making: processes, problems, and pathways. Crit Rev Environ Sci Technol 35:37
Thanikaivelan P, Saravanabhavan S, Chandrasekaran B, Rao JR, Nair BU, Ramasami T (2005b) A novel single step process for dehairing and fibre opening using enzymes. Applied for Patents in India and PCT Countries
Thanikaivelan P, Bharath CK, Saravanabhavan S, Anandhi C, Chandrasekaran B, Rao JR, Nair BU (2006) Single step hair removal and fiber opening process: simultaneous and successive addition of protease and α-amylase. J Am Leather Chem Assoc (in press)