Background: Chitin and chitosan are natural biopolymers found in shell of crustaceans, exoskeletons of insects and mollusks, as well as in the cell walls of fungi. These biopolymers have versatile applications in various fields such as biomedical, food industry, and agriculture. These applications are back to their biocompatibility, biodegradability, strong antibacterial effect, and non-toxicity. Outcomes: The fungal biopolymers have many features that made them more advantageous than those biopolymers from seafood waste origin. Chitin and chitosan are not components of cell wall in all fungal species. The fungal classes of Basidiomycetes, Ascomycetes, Zygomycetes, and Deuteromycetes are known to contain chitin and chitosan in their cell walls. The amounts and characters of fungal biopolymers are affected by many factors so they should be optimized before increasing the scale of production. The statistical design of experiments is the most recent and advanced approach for optimization of various factors with more reliable results. Conclusion: Although extensively studied, further studies concerning fungal chitin and chitosan should be conducted in order to be sure of safety for human use.

The present study aims to evaluate and validate a statistical model for maximizing biosurfactant productivity by Bacillus brevis using response surface methodology. In this respect, twenty bacterial isolates were screened for biosurfactant production using hemolytic activity, oil spreading technique, and emulsification index (E24). The most potent biosurfactant-producing bacterium (B. brevis) was used for construction of the statistical response surface model. The optimum conditions for biosurfactant production by B. brevis were: 33 °C incubation temperature at pH 8 for 10 days incubation period and 8.5 g/L glucose concentration as a sole carbon source. The produced biosurfactant (BS) (73%) exhibited foaming activity, thermal stability in the range 30–80 °C for 30 min., pH stability, from 4 to 9 and antimicrobial activity against (Escherichia coli). The BS gave a good potential application as an emulsifier.

Graphical abstractSize distribution of tellurium nanoparticles produced by Aspergillus welwitschiae F5k.

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Background: The aim of the current study based on the production and characterization of exopolysaccharides (EPSs) isolated from marine sediment of the Mediterranean and Red Seas is to study its cytotoxic activity against HepG2 cells. Results: Eleven isolates have the ability to produce EPSs and also decreased the viability of HepG2 cell line in different manners. The five most promising isolates that produce high yield of EPSs and high cytotoxicity were identified by 16S RNA as Brevundimonas subvibrioides MSA1, Bacillus thuringiensis E4, Bacillus amyloliquefaciens MGA2, Pseudomonas fluorescens SGA3, and Advenella Kashmirensis NRC-7. The chemical composition of the following EPSs (M1, M3, M6, M15, M19, E2, E4, E10, S5, S7, and S11) demonstrates that they are acidic sulfated heteropolysaccharides with different relative ratios of monosugars of glucose, mannose, galactose, glucouronic acid, and mannouronic acid. The average molecular weights from 1.94 × 10 4 to 7.95 × 10 5 g/mol and the number average molecular weight from 1.51 × 10 4 to 7.53 × 10 5 g/mol. FTIR spectrum of the five EPSs indicated the presence of sulfate and carboxylic groups in different percentages. Conclusions: The EPSs produced from marine bacteria are very promising for treating the HepG2 cells.

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The present investigation, focused on screening of various fungal species for Lovastatin production using different agro-based wastes, also, for maximizing lovastatin productivity by isolated Aspergillus fumigatus using response surface methodology (RSM). The following substrates (Olive cake; Pea pods; sugarcane bagasse; wheat bran; rice hulls; beet peel; Potato peel and groundnut shells) were screened to evaluate their effectiveness for lovastatin production, using different fungal species, (Aspergillus niger; Rhizopus oligosporus; Penicillium citrinum and isolated Aspergillus fumigatus) under solid state fermentation (SSF). Wheat bran was the most suitable substrate for lovastatin production with all fungal species. Optimum conditions of lovastatin production by wheat bran have been attained efficiently by response surface methodology (RSM) using isolated Aspergillus fumigatus under solid state fermentation (SSF). The lovastatin yield of (3.353 mg/g DFM) was obtained at an optimum temperature of 28 °C; pH of 5.00; initial moisture content of 70% and incubation period of 12 days. This Lovastatin has the possibility to use in different therapeutic applications.