Lignin nanoparticles enter the scene: A promising versatile green tool for multiple applications.

Strategies to take advantage of residual lignin from industrial processes are well regarded in the field of green chemistry and biotechnology. Quite recently, researchers transformed lignin into nanomaterials, such as nanoparticles, nanofibers, nanofilms, nanocapsules and nanotubes, attracting increasing attention from the scientific community. Lignin nanoparticles are seen as green way to use high-value renewable resources for application in different fields because recent studies have shown they are non-toxic in reasonable concentrations (both in vitro and in vivo assays), inexpensive (a waste generated in the biorefinery, for example, from the bioethanol platform) and potentially biodegradable (by fungi and bacteria in nature). Promising studies have tested lignin nanoparticles for antioxidants, UV-protectants, heavy metal absorption, antimicrobials, drugs carriers, gene delivery systems, encapsulation of molecules, biocatalysts, supercapacitors, tissue engineering, hybrid nanocomposites, wound dressing, and others. These nanoparticles can be produced from distinct lignin types and by different chemical/physical/biological methods, which will result in varied characteristics for their morphology, shape, size, yield and stability. Therefore, taking into account that the theme "lignin nanoparticles" is a trending topic, this present review is emerging and has the discuss the current status, covering from concepts, the formation mechanism, synthesis methods and applications, to the future perspectives and challenges linked to lignin-based nanomaterials, aiming at the viability and commercialization of this biotechnological product.

Penicillium echinulatum secretome analysis reveals the fungi potential for degradation of lignocellulosic biomass.

BACKGROUND: The enzymatic degradation of lignocellulosic materials by fungal enzyme systems has been extensively studied due to its effectiveness in the liberation of fermentable sugars for bioethanol production. Recently, variants of the fungus Penicillium echinulatum have been described as a great producer of cellulases and considered a promising strain for the bioethanol industry. RESULTS: Penicillium echinulatum, wild-type 2HH and its mutant strain S1M29, were grown on four different carbon sources: cellulose, sugar cane bagasse pretreated by steam explosion (SCB), glucose, and glycerol for 120 h. Samples collected at 24, 96, and 120 h were used for enzymatic measurement, and the 96-h one was also used for secretome analysis by 1D-PAGE LC-MS/MS. A total of 165 proteins were identified, and more than one-third of these proteins belong to CAZy families. Glycosyl hydrolases (GH) are the most abundant group, being represented in larger quantities by GH3, 5, 17, 43, and 72. Cellobiohydrolases, endoglucanases, ß-glycosidases, xylanases, ß-xylosidases, and mannanases were found, and in minor quantities, pectinases, ligninases, and amylases were also found. Swollenin and esterases were also identified. CONCLUSIONS: Our study revealed differences in the two strains of P. echinulatum in several aspects in which the mutation improved the production of enzymes related to lignocellulosic biomass deconstruction. Considering the spectral counting analysis, the mutant strain S1M29 was more efficient in the production of enzymes involved in cellulose and hemicellulose degradation, despite having a nearly identical CAZy enzymatic repertoire. Moreover, S1M29 secretes more quantities of protein on SCB than on cellulose, relevant information when considering the production of cellulases using raw materials at low cost. Glucose, and especially glycerol, were used mainly for the production of amylases and ligninases.

Morphogenesis and production of enzymes by Penicillium echinulatum in response to different carbon sources.

The effect of different carbon sources on morphology and cellulase and xylanase production of Penicillium echinulatum was evaluated in this work. Among the six carbon sources studied, cellulose and sugar cane bagasse were the most suitable for the production of filter paper activity, endoglucanases, xylanases, and ß-glucosidases. However, sucrose and glucose showed ß -glucosidase activities similar to those obtained with the insoluble sources. The polyacrylamide gels proved the enzymatic activity, since different standards bands were detected in the media mentioned above. Regarding morphology, it was observed that the mycelium in a dispersed form provided the greatest enzymatic activity, possibly due to greater interaction between the substrate and hyphae. These data are important in understanding the physiology of fungi and could contribute to obtaining enzyme with potential application in the technology of second generation ethanol.