African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12227

Full Length Research Paper

Statistical optimization of rapid production of cellulases from Aspergillus niger MA1 and its application in bioethanol production from rice hulls

Mohammad M. El-Metwally*
  • Mohammad M. El-Metwally*
  • Botany and Microbiology Department, Faculty of Science, Damanhour University, Egypt.
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Amal M. El-Sharkawy
  • Amal M. El-Sharkawy
  • Botany and Microbiology Department, Faculty of Science, Mansoura University, Egypt.
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Adel A. El-Morsy
  • Adel A. El-Morsy
  • Botany and Microbiology Department, Faculty of Science, Mansoura University, Egypt.
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Salah M. El-Dohlob
  • Salah M. El-Dohlob
  • Botany and Microbiology Department, Faculty of Science, Mansoura University, Egypt.
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  •  Received: 03 June 2014
  •  Accepted: 15 August 2014
  •  Published: 03 September 2014

Abstract

The aim of this study was the utilization of rice hulls (RH) as a clean, cost effective, renewable and abundant agro-waste in bioethanol production by simple and applicable methods; for this purpose Aspergillus niger MA1 was isolated from RH and selected from many other isolates. This isolate produced 15.0, 3.38 and 49.1 U/g RH for CMCase, FPase and β-glucosidase, respectively, by solid state fermentation of RH after 36 h. The cellulases of the fungus showed good thermal and pH stability with maximum activity at 50°C and pH 5. An increase in cellulases productivity by statistical optimization and multi-response of SSF medium was revealed. Addition of 0.25% brej 35 to tap water or saline is very effective in elution of A. niger MA1. Cellulase which was successfully used in saccharification of steam explosion pretreated RH, revealed 16.36 g/L reducing sugars and subsequently fermentation by Saccharomyces cerevisiae which produced 9.42 g/L ethanol after 24 h.

 

Key words: Rice hulls, bioethanol, cellulases, solid state fermentation, Aspergillus niger MA1, statistical optimization, multi-response.