Microalgae are a source of numerous compounds that can be used in many branches of industry. Synthesis of such compounds in microalgal cells can be amplified under stress conditions. Exposure to various metals can be one of methods applied to induce cell stress and synthesis of target products in microalgae cultures. In this review, the potential of producing diverse biocompounds (pigments, lipids, exopolymers, peptides, phytohormones, arsenoorganics, nanoparticles) from microalgae cultures upon exposure to various metals, is evaluated. Additionally, different methods to alter microalgae response towards metals and metal stress are described. Finally, possibilities to sustain high growth rates and productivity of microalgal cultures in the presence of metals are discussed.

This critical review article presents the current state of knowledge on isomalto-oligosaccharides, some well known functional oligosaccharides in Asia, to evaluate their potential as emergent prebiotics in the American and European functional food market. It includes first a unique inventory of the different families of compounds which have been considered as IMOs and their specific structure. A description has been given of the different production methods including the involved enzymes and their specific activities, the substrates, and the types of IMOs produced. Considering the structural complexity of IMO products, specific characterization methods are described, as well as purification methods which enable the body to get rid of digestible oligosaccharides. Finally, an extensive review of their techno-functional and nutritional properties enables placing IMOs inside the growing prebiotic market. This review is of particular interest considering that IMO commercialization in America and Europe is a topical subject due to the recent submission by Bioneutra Inc. (Canada) of a novel food file to the UK Food Standards Agency, as well as several patents for IMO production.

No abstract

No abstract

High-purity cellulose nanofibers were isolated from wheat straw through an environmentally friendly, multistep treatment process that combined steam explosion, microwave-assisted hydrolysis, and microfluidization. The cellulose content of the processed nanofibers increased from 44.81% to 94.23%, whereas the hemicellulose and lignin contents significantly decreased. Scanning electron microscopy revealed the effects of the isolation treatments on fiber morphology and width. Atomic force microscopy was used to observe the changes in the components, surface roughness, and crystallinity of the fibers. Transmission electron microscopy showed long, loose nanofiber bundles that were 10–40 nm wide with an average individual diameter of 5.42 nm. Fourier transform infrared spectroscopy showed that noncellulosic components were effectively removed. X-ray diffraction analysis revealed the improved crystallinity of the processed fibers, as well as the partial crystalline transformation of cellulose I to cellulose II. Thermogravimetric analysis and derivative thermogravimetric results showed the enhanced thermal properties of the nanofibers. The removal of hemicellulose and lignin increased the crystallinity of the fibers, thus enhancing the thermal properties of the processed fibers. Results indicated that the efficient, environmentally friendly, multistep treatment process yields nanofibers with potential advanced applications.

In this review, the effect of organic solvents on microalgae cultures from molecular to industrial scale is presented. Traditional organic solvents and solvents of new generation-ionic liquids (ILs), are considered. Alterations in microalgal cell metabolism and synthesis of target products (pigments, proteins, lipids), as a result of exposure to organic solvents, are summarized. Applications of organic solvents as a carbon source for microalgal growth and production of target molecules are discussed. Possible implementation of various industrial effluents containing organic solvents into microalgal cultivation media, is evaluated. The effect of organic solvents on extraction of target compounds from microalgae is also considered. Techniques for lipid and carotenoid extraction from viable microalgal biomass (milking methods) and dead microalgal biomass (classical methods) are depicted. Moreover, the economic survey of lipid and carotenoid extraction from microalgae biomass, by means of different techniques and solvents, is conducted.

No abstract

No abstract