Current Research Journal of Biological Sciences 2(2): 124-131, 2010 ISSN: 2041-0778 © Maxwell Scientific Organization, 2010 Submitted Date: November 14, 2009 Accepted Date: December 07, 2009 Published Date: March 10, 2010 Corresponding Author: Dr. D. Dhanasekaran, Department of Microbiology, Bharathidasan University, Tiruchirappalli - 620 024, Tamil Nadu, India Tel: +91-9486258493 124 Isolation and Screening of Keratinolytic Actinobacteria form Keratin Waste Dumped Soil in Tiruchirappalli and Nammakkal, Tamil Nadu, India Subhasish Saha and Dharumadurai Dhanasekaran Department of Microbiology, Bharathidasan University, Tiruchirappalli – 620 024, Tamil Nadu, India Abstract: The aim of this study was to isolate keratinolytic Actinobacteria from feather dumping soil. Feather dumping soil was collected from several areas in Tiruchirappalli, Nammakkal, Tamil Nadu, and India. Twenty two isolates were selected after growth on Bennett’s agar and they named as SD1 to SD22. All the twenty two isolates were subjected for primary screening on milk agar plates and among twenty two isolates ten were showing proteolytic activity in terms of making clear zone surrounding their colony on the Milk agar medium. The ten positive isolates were again subjected for the secondary screening on Feather Broth and three isolates, SD5, SD6 and SD7 were showing degradation of feather during their growth. Though the degradation process was taking long time, all these three isolates achieved complete degradation of feather between 20 to 25 days and they used feather as the sole organic source for carbon, sulfur and energy. These novel keratinolytic Actinobacterial isolates have potential biotechnological use in processes involving keratin hydrolysis. Key words: Bennett’s Agar, keratin hydrolysis, keratinolytic Actinobacteria, milk agar, modified basal liquid medium INTRODUCTION Feather waste, generated in large quantities as a by- product of commercial poultry processing, is nearly pure keratin protein (Moran et al. , 1966). Keratin in its native state is not degradable by common proteolytic enzymes such as trypsin, pepsin and papain. However keratin does not accumulate in nature and keratinolytic activity has been reported for species of Aspergillus, Ctenomyces (Gupta et al. , 1950), Bacillus sp. (Molyneaux, 1959) and Streptomyces (Noval and Nickerson, 1959). Currently, feather waste is utilized on a limited basis as a dietary protein supplement for animal feed stuffs. A current value-added use for feathers is the conversion to feather meal, a digestible dietary protein for animal feed, using physical and chemical treatments. These methods can destroy certain amino acids and decrease protein quality and digestibility (Moritz and Latshaw, 2001; Wang and Parsons, 1997). The nutritional inferiority and insolubility of native feather protein derive from the composition and molecular configuration of constituent amino acids that ensure the structural rigidity of feathers (Parry and North, 1998). Resistance to proteolytic enzymes has been attributed to the complex structure of $-keratin filaments. In addition, disulfide cross-links produce a compact three- dimensional network (Bradbury, 1973), as a result of intermolecular disulfide bonds between rod domains and terminal domains of the constituent molecules (Parry and North, 1998). The nutritional upgrading of feather meal through microbial or enzymatic treatment has been described. Feather meal fermented with Streptomyces fradiae and supplemented with methionine resulted in a growth rate of broilers comparable with those fed isolated soybean protein (Elmayergi and Smith, 1971). The crude keratinase enzyme increased the digestibility of commercial feather meal and could replace as much as 7% of the dietary protein for growing chicks (Odetallah et al., 2003). Keratinolytic microorganisms and their enzymes may be used to enhance the digestibility of feather keratin. They may have important applications in processing keratin-containing wastes from poultry and leather industries through the development of non-polluting methods (Onifade et al., 1998). Generally, an increase in keratinolytic activity is associated with thermophilic organisms, which require high energy, inputs to achieve maximum growth and the decomposition of keratin wastes (Friedrich and Antranikian, 1996; Nam et al., 2002). The Actinobacterial isolates can degrade raw feathers and therefore useful to develop efficient processes involving keratin substrates. In this study, we described the collection of feather dumping soil from several areas, isolation of Actinobacteria from feather dumping soil and selection of keratinolytic Actinobacterial isolates by performing primary and secondary screening.