A Comparative Proteomic Study of Thermobifida Cellulosilytica TB100T Secretome Grown on Carboxymethylcellulose and Rice Straw

Mai H. Elmahdy1, *, Ahmed F. Azmy1, Eman El-Gebaly1, 2, Amal Saafan3, Yasser Gaber1, 4
1 Department of Microbiology and Immunology, Faculty of Pharmacy, Beni-Suef University, 62511, Beni-Suef, Egypt
2 Department of Microbiology and Immunology, Faculty of Pharmacy, October 6 University, 12585, Cairo, Egypt
3 Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Menoufia University, Shebeen El-kom, 51132, Egypt
4 Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy, Mutah University, 61710, Mutah, Jordan

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© 2020 Elmahdy et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: ( This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Department of Microbiology and Immunology, Faculty of Pharmacy, Beni-Suef University, 62511, Beni-Suef, Egypt; Tel: +201096656500; Fax: +20 82 216 2136; E-mail:



Cellulose, the major component of the plant cell wall, is the most abundant and cheap polymer on earth. It can be used by varieties of cellulolytic enzymes. Cellulases can hydrolyze cellulose to its glucose monomers, which can be fermented to many biotechnological products, such as biochemicals, bioplastics, and biofuels. Actinomycetes are potential sources of cellulases.


The current study sheds light on the cellulolytic activity of Thermobifida cellulosilytica, a previously isolated thermophilic actinomycete, and the analysis of the lignocellulases produced in the secretome as a result of induction by different carbon sources.


The cellulolytic activity was qualitatively confirmed by Congo red method showing a large halo zone around the colonies. The activity was also assayed using the 3,5-dinitrosalicylic acid (DNS) method. The secretome analysis was conducted by liquid chromatography-tandem mass spectroscopy (LC-MS/MS) based proteomic approach.


The cellulolytic activity increased by two folds upon the growth of T. cellulosilytica on rice straw (RS) as a complex substrate comparatively to Carboxymethylcellulose (CMC) as a simple one. These results were highly assured by LC-MS/MS. Where more proteins (n=31) were produced in the RS secretome, CMC produced only six proteins, including only one cellulase. Different classes of proteins produced in the RS secretome were cellulases (26%), hemicellulases (16%), proteases (10%), and others (48%).


Lignocellulases are inducible enzymes. RS as a complex substrate induced T. cellulosilytica for the expression of more lignocellulolytic enzymes than CMC.

Keywords: Carboxymethylcellulose , Carboxymethylcellulase , Thermobifida cellulosilytica , Rice straw , Secretome analysis , LC-MS/MS .