Biomass valorization: Sustainable methods for the production of hemicellulolytic catalysts from thermoanaerobacterium thermostercoris strain buff

Processing and selection of fruits and vegetables generate high quantities of wastes that represent an economic and environmental issue for the agroindustry sector. According to the so-called “biorefinery” approach, this biomass can be exploited for the recovery of value-added molecules. In this study, the residues of industrial processing of tomato (Lycopersicon esculentum variety “Hybrid Rome”), fennel (Foeniculum vulgare), potato (Solanum tuberosum) and carrot (Daucus carota) were used as sole carbon sources to support cheap and sustainable microbial growth as well as the production of secondary metabolites (hydrogen and ethanol) by Thermoanaerobacterium thermostercoris strain BUFF, a thermophilic anaerobic microorganism isolated from buffalo-dung compost. Moreover, the use of hemicellulolytic enzymes of T. thermostercoris was assayed in the bioconversion reaction of the polymer fraction extracted from the rhizome of giant reed (Arundo donax) and of the leaves and stems of cardoon (Cynara cardunculus), dedicated non-food crops employed in energy supply

Parageobacillus thermantarcticus, an Antarctic Cell Factory: From Crop Residue Valorization by Green Chemistry to Astrobiology Studies

Knowledge of Antarctic habitat biodiversity, both marine and terrestrial, has increased considerably in recent years, causing considerable development in the studies of life science related to Antarctica. In the Austral summer 1986–1987, a new thermophilic bacterium, Parageobacillus thermantarcticus strain M1 was isolated from geothermal soil of the crater of Mount Melbourne (74°22′ S, 164°40′ E) during the Italian Antarctic Expedition. In addition to the biotechnological potential due to the production of exopolysaccharides and thermostable enzymes, successful studies have demonstrated its use in the green chemistry for the transformation and valorization of residual biomass and its employment as a suitable microbial model for astrobiology studies. The recent acquisition of its genome sequence opens up new opportunities for the use of this versatile bacterium in still unexplored biotechnology sectors

Prokaryotic Diversity of the Composting Thermophilic Phase: The Case of Ground Coffee Compost

Waste biomass coming from a local coffee company, which supplied burnt ground coffee after an incorrect roasting process, was employed as a starting material in the composting plant of the Experimental Station of the University of Naples Federico II at Castel Volturno (CE). The direct molecular characterization of compost using 13C-NMR spectra, which was acquired through cross-polarization magic-angle spinning, showed a hydrophobicity index of 2.7% and an alkyl/hydroxyalkyl index of 0.7%. Compost samples that were collected during the early “active thermophilic phase” (when the composting temperature was 63 C) were analyzed for the prokaryotic community composition and activities. Two complementary approaches, i.e., genomic and predictive metabolic analysis of the 16S rRNA V3–V4 amplicon and culture-dependent analysis, were combined to identify the main microbial factors that characterized the composting process. The whole microbial community was dominated by Firmicutes. The predictive analysis of the metabolic functionality of the community highlighted the potential degradation of peptidoglycan and the ability of metal chelation, with both functions being extremely useful for the revitalization and fertilization of agricultural soils. Finally, three biotechnologically relevant Firmicutes members, i.e., Geobacillus thermodenitrificans subsp. calidus, Aeribacillus pallidus, and Ureibacillus terrenus (strains CAF1, CAF2, and CAF5, respectively) were isolated from the “active thermophilic phase” of the coffee composting. All strains were thermophiles growing at the optimal temperature of 60 C. Our findings contribute to the current knowledge on thermophilic composting microbiology and valorize burnt ground coffee as waste material with biotechnological potentialities

Novel psychrophiles and exopolymers from permafrost thaw lake sediments

Thermokarst lakes are one of the most abundant types of microbial ecosystems in the circumpolar North. These shallow basins are formed by the thawing and collapse of ice-rich permafrost, with subsequent filling by snow and ice melt. Until now, permafrost thaw lakes have received little attention for isolation of microorganisms by culture-based analysis. The discovery of novel psychrophiles and their biomolecules makes these extreme environments suitable sources for the isolation of new strains, including for potential biotechnological applications. In this study, samples of bottom sediments were collected from three permafrost thaw lakes in subarctic Québec, Canada. Their diverse microbial communities were characterized by 16S rRNA gene amplicon analysis, and subsamples were cultured for the isolation of bacterial strains. Phenotypic and genetic characterization of the isolates revealed affinities to the genera Pseudomonas, Paenibacillus, Acinetobacter, Staphylococcus and Sphingomonas. The isolates were then evaluated for their production of extracellular enzymes and exopolymers. Enzymes of potential biotechnological interest included α and β-glucosidase, α and β-maltosidase, β-xylosidase and cellobiohydrolase. One isolate, Pseudomonas extremaustralis strain 2ASCA, also showed the capability to produce, in the loosely bound cell fraction, a levan-type polysaccharide with a yield of 613 mg/L of culture, suggesting its suitability as a candidate for eco-sustainable alternatives to commercial polymers

Degradative actions of microbial xylanolytic activities on hemicelluloses from rhizome of Arundo donax.

Polysaccharidases from extremophiles are remarkable for specific action, resistance to different reaction conditions and other biotechnologically interesting features. In this article the action of crude extracts of thermophilic microorganisms (Thermotoga neapolitana, Geobacillus thermantarcticus and Thermoanaerobacterium thermostercoris) is studied using as substrate hemicellulose from one of the most interesting biomass crops, the giant reed (Arundo donax L.). This biomass can be cultivated without competition and a huge amount of rhizomes remains in the soil at the end of cropping cycle (10–15 years) representing a further source of useful molecules. Optimization of the procedure for preparation of the hemicellulose fraction from rhizomes of Arundo donax, is studied. Polysaccharidases from crude extracts of thermophilic microorganisms revealed to be suitable for total degradative action and/or production of small useful oligosaccharides from hemicelluloses from A. donax. Xylobiose and interesting tetra- and pentasaccharide are obtained by enzymatic action in different conditions. Convenient amount of raw material was processed per mg of crude enzymes. Raw hemicelluloses and pretreated material show antioxidant activity unlike isolated tetra- and pentasaccharide. The body of results suggest that rhizomes represent a useful raw material for the production of valuable industrial products, thus allowing to increase the economic efficiency of A. donax cultivation

Comparison of industrial Saccharomyces cerevisiae strains for second generation bioethanol production

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Lemon peel polyphenols affect invasiveness of human gastric AGS and MKN28 cells by inhibition of IL-6 induced matrix metalloproteinase-9/2

Polyphenols are very abundant in food of mediterranean diet and, in the last years, they are subjects of increasing scientific interest for their potential health benefits against development of cancer, cardiovascular diseases, diabetes, osteoporosis and neu- rodegenerative diseases. In this study, we investigated the effects of lemon peel extracts (LPE) on human gastric adenocarcinoma MKN28 and AGS cell lines. First, we evaluated the effect of LPE on the invasive ability of AGS and MKN28 cells stimulated with IL-6, a pro-inflammatory factor. Migration and Matrigel invasion assays demonstrated that the pre-treatment with LPE (0.5 or 1 lg/mL gallic acid equivalent) provoked an inhibition of cell invasiveness induced by IL-6. In addition, LPE preincubation prevented the increase of Matrix Metalloproteinases (MMP)-9/2 mRNA and protein levels, whose expression is up-regulated by IL-6. Our results indicated that the pre-treatment with LPE was able to reduce MMP-9/2 expression at both protein and enzyme activity levels in the conditioned media of IL-6 stimulated MKN- 28 and AGS cells. Finally, we have analyzed the effect of LPE on STAT3 levels, a transcriptional factor that becomes activated after phosphorylation by IL-6. In conclusion, our results suggest that LPE reduces the invasiveness of gastric MKN-28 and AGS cancer cells through the reduction of IL-6 induced MMP-9/2 up- regulation. Therefore, our data confirm the protective effects that LPE could exert against the metastatic process in gastric cancer

Lemon Peel Polyphenol Extract Reduces Interleukin-6-Induced Cell Migration, Invasiveness, and Matrix Metalloproteinase-9/2 Expression in Human Gastric Adenocarcinoma MKN-28 and AGS Cell Lines

Among plant polyphenols, lemon peels extract (LPE) from the residues of the industrial processing of lemon (Citruslimon) shows anti-proliferative properties in cancer cells and anticholinesterase activity. In this study, we analyze the anti-cancer properties of LPE on migration and invasiveness in MKN-28 and AGS human gastric cancer cell lines either in the absence or presence of the pro-inflammatory cytokine IL-6. We find that the pretreatment with non-cytotoxic concentrations (0.5-1 μg/ml of gallic acid equivalent) of LPE inhibits interleukin-6 (IL-6)-induced cell migration and invasiveness in MKN-28 and AGS cells, as analyzed by wound and matrigel assays. Pretreatment with LPE is able to prevent either IL-6-induced matrix metalloproteinases (MMP)-9/2 activity, as assessed by gel zymography, or mRNA and protein MMP-9/2 expression, as evaluated by qPCR and Western blotting analysis, respectively. These LPE effects are associated with an IL-6-dependent STAT3 signaling pathway in MKN-28 and AGS cells. Furthermore, LPE shows acetylcholinesterase inhibitory activity when assayed by the Ellman method. In conclusion, our results demonstrate that LPE reduces the invasiveness of gastric MKN-28 and AGS cancer cells through the reduction of IL-6-induced MMP-9/2 up-regulation. Therefore, these data suggest that LPE exerts a protective role against the metastatic process in gastric cancer