Biological evaluation of extremophilic Chaetomium species for the production of metabolites for food and pharmaceutical uses

Project leaders

Antonietta Mello, Mohamed Ahmed Abdel-azeem

Agreement

EGITTO - ASRT - Academy of Scientific Research and Technology

Call

CNR/ASRT biennio 2018-2019 2018-2019

Department

Biology, agriculture and food sciences

Thematic area

Biology, agriculture and food sciences

Status of the project

New

Research proposal

Chaetomium is a filamentous fungus and a large genus in the family Chaetomiaceae (Ascomycota) which currently encompasses 163 species. Taxa in this genus are considered to be a rich source of novel and bioactive secondary metabolites of great importance for food and pharmaceutical uses. Many of these compounds have been reported to possess significant biological activities, i.e. antitumor, antimalarial, cytotoxic, antibiotic, antioxidant, cellulase and ligninases enzymes (Blunt et al. 2011; Zhang et al. 2012; Nagadesi & Arya, 2013). Antibiotic resistance has become a public health priority worldwide and its spread is currently faster compared to the development of new molecules. Italy is among a group of EU countries with the highest percentage of bacteria resistance to antibiotics (ECDC) while in Egypt, patients can purchase antibiotics without a prescription, and that overuse of antibiotics can lead to bacterial antibiotic resistance.
Recently, there has been a great deal of attention toward free radical chemistry that triggers a number of human diseases. Application of external source of antioxidants can assist in coping this oxidative stress, nevertheless synthetic antioxidants have recently been reported to be dangerous for human health. Thus, there is a strong request for effective, nontoxic natural compounds with antioxidative activities.
Our goal is to isolate and characterize Chaetomium species from different extreme habitats in Egypt and Italy by polyphasic approaches, investigate their antimicrobial activities towards multidrug resistance bacteria & fungi and their production of enzymes and antioxidants molecules.
Chaetomium will be isolated from different habitats including soil (desert, salt-marshes, cultivated), herbivore dung, stored seeds and grains, mangrove, medicinal plants, deteriorated archeological woods and compositing materials in order to draw a picture as complete as possible about the biodiversity of Chaetomium spp. in both countries, and its habitat preference. Fungi will be identified according to a polyphasic approach, which merge together morphological, physiological, bioinformatic and molecular analyses. All the identified taxa will be preserved at the Mycotheca Universitatis Turinensis (MUT) of the University of Turin. Quantitative and qualitative estimation of some extracellular enzymes including chitinase & chitosanase, amylase, L-asparaginase, lipase, cellulase, xylanase and laccase will follow the relevant techniques some of which described in Wang et al. (2003) and Adiveppaand Basappa (2015). Different assays for the antioxidant activity will be set up and compared: 1,1-Diphenyl-2-picryl hydrazyl (DPPH) free radicals scavenging assay, reducing power measurement, determination of ferrous ion and nitric oxide (NO) scavenging activities, ,determination of total phenolic contents. To test antimicrobial activities towards multidrug resistant bacteria and fungi a preliminary screening of Chaetomium isolates versus reference strains of Gram + and Gram - using the Kirby Bauer test will be carried out. Taxa showing high inhibition activity will be tested versus MDR fungal and bacterial strains. The positive ones will be cultivated by an OSMAC (one-strain-many-compounds approach) in liquid/solid media to evaluate the MIC of the different culture extracts using 96-well based in vitro antimicrobial assay (Gnavi et al., 2016; Sarker et al., 2007). Active fractions will be further characterized with the help of other research groups with the requested skills to isolate and identify the active compounds. In parallel, the search and comparison of genes of interest for the production of a given enzyme or metabolite will be done in the available genomes of Chaetomium spp. for an in silico characterization of these genes and thus improving knowledge on this genus of fungi.


The cooperation will allow the exchanges of expertise between different groups about the most updated technique for the isolation, identification and characterization of a difficult but intriguing genus as Chaetomium whose metabolic potential still have to be unlocked. More in detail, the Chaetomium isolated will be screened for their capability to produce different bioactive molecules (antimicrobial and antioxidant compounds and enzymes) potentially useful in different fields of application. Moreover special attention will be paid on teaching techniques for the long-term preservation (lyophilization and cryopreservation) of fungal strains according to international standards as well as creating a database specifically dedicated to the conservation of all associated metadata to allow the birth of a microbial Biological resource Center (mBRC) in Egypt in line with the Best practices of MIRRI (Microbial Resource research Infrastructure - www.mirri.org). This mBRC hence, with the support of the Italian colleagues will guaranty: the security of microbial biodiversity according to best practices for future use and protection of public funding investment and legal certainty on genetic resources. It will allow a broader access to well identified and characterized material for the exploitation of microbial diversity and related data to boost knowledge transfer and innovation driving a successful bioeconomy. Finally, the collaboration will allow an increase level of education and training for students, researchers and staff of mBRC.
Expected outcomes:
i. identification of new taxa of Chaetomium from both countries as potential sources of new bioactive molecules;
ii. discovery of candidate molecules for new antimicrobial drug development.
iii. discovery of new isoforms of enzymes to be used in food industry
iv. discovery of new antioxidant molecules to be used in food, pharma or cosmetic industry
v. the creation of the first mBRC in Egypt.
VI. in silico characterization of genes of interest

Research goals

This work aimed to study the ecology and taxonomy of Chaetomium in Egypt & Italy and to survey and evaluate their potentiality to produce bioactive metabolites (antibiotics against drug resistant bacteria and fungi and some antioxidant molecules and enzymes useful in food, pharmaceutical and cosmetic sectors). To fulfill these objectives, a range of various habitats (mainly extreme and/or unexplored environments) will be collected. All the isolates will be screened for several useful properties in order to give as complete as possible a preliminary picture of the taxa of Chaetomium producing bioactive metabolites. The most promising strains for the production of antimicrobial and antioxidant compounds and enzymes will be deeper investigated through the involvement of other teams.
Moreover a great effort will be devoted to the training of students, researchers. More in detail the persons will be trained on all issues related to a proper fungal taxonomy and systematics including morphological, molecular, bioinformatic and phylogenetic aspects. Special attention will be given to teach the basic information to set up the first Egyptian fungal culture collection explaining both technical protocols for long-term preservation of fungal strains according to international standards as well as quality control procedures and IT procedures to create a database specifically dedicated to the conservation of all associated metadata.

Last update: 19/06/2025