Key determinants affecting sheep wool biodegradation directed by a keratinase-producing Bacillus subtilis recombinant strain

• Published in: Biodegradation (Dordrecht) Vol. 22; no. 1; pp. 111 - 128
• Main Authors: Zaghloul, Taha I, Embaby, Amira M, Elmahdy, Ahmed R
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01.02.2011; Springer Netherlands; Springer; Springer Nature B.V
• Subjects: A keratinase-producing Bacillus subtilis recombinant strain; Amino acids; Animals; Aquatic Pollution; Bacillus subtilis; Bacillus subtilis - enzymology; Bacillus subtilis - genetics; Bacillus subtilis - metabolism; Bacteria; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biodegradation; Biodegradation of pollutants; Biodegradation, Environmental; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Determinants; Distilled water; Drinking water; Environment and pollution; Fundamental and applied biological sciences. Psychology; Genetic Engineering; Geochemistry; Hydrolysates; Industrial applications and implications. Economical aspects; Life Sciences; Microbiology; Original Paper; OVAT; Peptide Hydrolases - genetics; Peptide Hydrolases - metabolism; Physicochemical key determinants; Proteins; Recombinant; Refuse Disposal - methods; Sheep; Sheep wool hydrolysis end products; Sheep wool waste; Sheep wool-based tap/distilled water medium; Soil Science & Conservation; Strain; Terrestrial Pollution; Waste Management/Waste Technology; Waste Water Technology; Water Management; Water Pollution Control; Wool; Wool - chemistry; Wool - metabolism; Wool - microbiology; Yeasts; Physicochemical key determinants; Sheep wool-based tap/distilled water medium; Sheep wool waste; Sheep wool hydrolysis end products; recombinant strain; A keratinase-producing; OVAT; Biodegradation; Water; Bacillus subtilis; A keratinase-producing Bacillus subtilis recombinant strain; Bacillaceae; Hydrolysis; Vertebrata; Mammalia; Bacillales; Bacteria; Sheep; Artiodactyla; Wastes; Wool; Ungulata
• ISSN: 0923-9820; 1572-9729
• DOI: 10.1007/s10532-010-9381-9

OVAT (one variable at a time) approach was applied in this study to screen the most important physicochemical key determinants involved in the process of sheep wool biodegradation. The process was directed by a keratinase-producing Bacillus subtilis DB 100 (p5.2) recombinant strain. Data indicate that, sheep wool could be degraded efficiently in cultures incubated at 30°C, with initial pH of 7 with agitation at 150 rpm. Two times autoclaved alkali treated and undefatted chopped sheep wool is more accessible to biodegradation. B. subtilis recombinant cells could utilize sheep wool as a sole source of carbon and nitrogen. Sheep wool-based modified basal medium II, lacking NH₄Cl and yeast extract, could greatly support the growth of these bacterial cells. Sheep wool biodegradation was conducted efficiently in the absence of kanamycin consequently; high stability of the recombinant plasmid (p5.2) represents a great challenge upon scaling up this process. Three key determinants (sheep wool concentration, incubation time and inoculum size) imposing considerable constraints on the process are highlighted. Sheep wool-based tap water medium and sheep wool-based distilled water medium were formulated in this study. High levels of released end products, produced from sheep wool biodegradation are achieved upon using these two sheep wool-based water media. Data indicate that, sheep wool hydrolysate is rich in some amino acids, such as tyrosine, phenylalanine, lysine, proline, isoleucine, leucine, valine, aspartic acid and glutamic acid. Moreover, the resulting sheep wool hydrolysate contains soluble proteins of high and intermediate molecular weights. The present study demonstrates a feasible, cheap, reproducible, efficient and rapid biotechnological approach towards utilization of raw sheep wool waste through a recombinant bacterium.