Biosynthesis of chitosan-Oligosaccharides (COS) by non-aflatoxigenic Aspergillus sp. strain EGY1 DSM 101520: A robust biotechnological approach. (January 2018)

• Record Type: Journal Article
• Authors: Embaby, Amira M.; Melika, Ramy R.; Hussein, Ahmed; El-Kamel, Amal H.; S.Marey, Heba
• Is Part Of: Process biochemistry. Volume 64(2018)
• Page Start: 16
• Page End: 30
• Publication Date: 2018-01
• Subjects: COS biosynthesis -- Non-aflatoxigenic Aspergillus sp. section flavi strain EGY1 DSM 101520 -- Statistical-Mathematical modeling -- Scaling up -- COS characterization; Biochemical engineering -- Periodicals; Biotechnology -- Periodicals; Biochemistry -- periodicals; Biotechnology -- periodicals; Chemical Engineering -- periodicals; Génie biochimique -- Périodiques; Biotechnologie -- Périodiques; Biochemical engineering; Biotechnology; Periodicals; 660.63
• DOI: 10.1016/j.procbio.2017.09.030
• Languages: English
• ISSNs: 1359-5113

Abstract

Graphical abstract: Highlights: Chitosan-Oligosaccharides (COS) were biosynthesized by Aspergillus sp. cells. COS biosynthesis was bench scale optimized via statistical-mathematical model. Optimal conditions were only 0.687% (w/v) LMWC in tap water and 25 °C. COS productivity in the laboratory scale fermenter was 5.34 gL −1 after 44 h. Partially acetylated COS heterogeneous mixture with DPs (2–11) was proved. Abstract: Currently applied methodologies (acidic or enzymatic chitosanolysis) towards synthesis of Chitosan- Oligosaccharides (COS) are faced with some drawbacks that confine their potential in biotechnological applications. The present work addresses a novel tailored method as an alternate to biosynthesize COS. An empirical statistical-mathematical approach [Plackett-Burman. Design (PBD) followed by Box-Behnken design (BBD)] was employed to optimize COS biosynthesis by an endo -chitosanase non-aflatoxigenic producing Aspergillus sp. section Flavi strain EGY1 DSM 101520 whole cells. Optimal levels localized by BBD for three key determinants were 0.687% (w/v) low molecular weight chitosan (LMWC), 25 °C incubation temperature and 72–96 h incubation time, along with 2.0 gL −1 maximal level of COS, achieving 94.7% model adequacy upon growing the fungus on LMWC-based tap water medium [merely 0.687% (w/v) LMWC]. Batch mode scaling up in the laboratory scale fermenter achieved 5.34 gL −1 of COS after 44 h with 2.67 fold enhancement. Partially acetylated hetero-oligomers with DPs (2–11) of the water-soluble COS were proved by TLC, MALDI-TOF-MS, 1 H NMR, 13 C NMR and FTIR. To the best of the authors' knowledge, the present work is the first study highlighting a novel, robust, cheap, environmentally safe, reproducible approach to biosynthesize COS by fungal whole cells.