China 
Africa 
Explore chapters and articles related to this topic
Bioconversion of Waste Biomass to Bioethanol
Published in Prakash Kumar Sarangi, Sonil Nanda, Bioprocessing of Biofuels, 2020
Prakash Kumar Sarangi, Sonil Nanda
Several microorganisms including fungi (e.g. Aspergillus, Candida shehatae, Fusarium sp., Kluyveromyces sp., Neurospora sp., Phanerochaete sp., Penicillium sp., Pichia kudriavzevii, Saccharomyces cerevisiae, Schizophyllum sp., Sclerotium sp., Trichoderma sp., etc.) and bacteria (e.g. Acetovibrio sp., Bacillus sp., Clostridium thermocellum, Erwinia sp., Escherichia coli, Klebsiella oxytoca, Ruminococcus sp., Zymomonas mobilis, etc.) accomplish fermentation of biomass hydrolysates to produce ethanol (Nanda et al. 2014b). S. cerevisiae is a model microorganism for ethanol fermentation because of its high efficiency, stability, a faster rate of sugar conversion and high solvent (alcohol) tolerance. Moreover, it is also considered as GRAS (generally regarded as safe). S. cerevisiae is also a potential producer of zymase, an enzyme complex that manifests the biocatalysis of sugar fermentation into ethanol and CO2 (Lin and Tanaka 2006).
Cellulose Bioconversion Technology
Published in Charles E. Wyman, Handbook on Bioethanol, 2018
A variety of yeasts, such as Saccharomyces cerevisiae, S. uvarum, Kluyveromyces fragilis, Candida pseudotropicalis, and Pachysolen tannophilus, and bacteria, such as Zymomonas mobilis and C. thermocellum can efficiently ferment glucose to ethanol [5]. The use of Z. mobilis for ethanol production from sugar cane syrup has been successfully scaled up yielding up to 10% ethanol by volume [23]. Recently, the cloning of heterologous genes in bacteria such as Escherichia coli [24], Klebsiella oxytoca [25], and Z. mobilis [26] has led to the construction of organisms capable of converting hexoses and pentoses to ethanol (cofermentation). Nevertheless, S. cerevisiae strains still remain the most commonly used ethanologens for starch and cellulosic biomass sugars.
Environmental Effects of the Application of Iron Nanoparticles for Site Remediation
Published in Marta I. Litter, Natalia Quici, Martín Meichtry, Iron Nanomaterials for Water and Soil Treatment, 2018
Ekain Cagigal, Marta Ocejo, Jose Luis R. Gallego, Ana I. Pelaez, Eduardo Rodriguez-Valdes
The sensitivity or tolerance to nZVI differs between the bacterial genera or even between different species. Several Klebsiella species are resistant to high doses of nZVI [37, 48] and the higher resistance of Bacillus subtilis to Fe2+ than E. coli or Pseudomonas fluorescens in in-vitro experiments is conceivably due to its higher negative charge that gives rise to a higher nZVI electrostatic repulsion (see above) and as a consequence to a reduced toxicity [42, 49]. However, Fe3+ was shown to have stronger inactivation effects on B. subtilis than Fe2+, especially at higher dosages [50]. As well as the mechanisms of cellular damage are being elucidated, the resistance responses are also revealed. Some results suggest that one of the protective strategies developed by the organisms is the formation of spores, preventing bacteria from direct contact to iron NPs [51]. Another biological response might be the downregulation of membrane, and periplasmic proteins (porins, iron ABC transporter, siderophore receptor) involve in iron uptake [52, 53]. Remarkably, bacterial cells in stationary growth are less sensitive to nZVI compared with those in lag or exponential phase, being this likely related to the higher expression of several genes involved in cell stress response during stationary growth [2, 54]. Otherwise, schemes based on the production of extracellular polymeric substances have been suggested, aiming at bonding to nZVI and thus constraining interaction between iron and bacteria and, therefore, its harmful effects [55, 56]. Besides the aforementioned mechanisms preventing iron uptake by cells, other responses are developed for minimizing oxidative stress. The high tolerance to nZVI of some bacteria as Klebsiella oxytoca seems to be related with adaptative stress response, involving tryptophanase and indole as a signal molecule of environmental disturbances [48]. In other cases, the defensive response has been linked to the maintenance of cellular homeostasis and the upregulation of proteins involved in reducing intracellular oxidative stress, as catalase, a key component for detoxification of reactive oxygen species as H2O2 [36,51–53].
Occurrence of antibiotic resistance among Enterobacterales isolated from raw and ready-to-eat food – phenotypic and genotypic characteristics
Published in International Journal of Environmental Health Research, 2022
Urszula Zarzecka, Wioleta Chajęcka-Wierzchowska, Anna Zadernowska
A total number of 92 Enterobacterales isolates were obtained from 80 food samples. The largest number of isolates (n = 46; 50%) came from raw meat samples. Number of 30 isolates (32.6%) were obtained from raw plant-derived food, ready-to-eat meat products were a source of 16 isolates (17.3%). There were no Enterobacterales isolates from salads. In total, 62 isolates (67.4%) were obtained from food of animal origin, and 30 (32.6%) from food of plant origin. The following species were identified: Enterobacter cloacae (42.4%), Escherichia coli (9.8%), Proteus mirabilis, Proteus penneri, Salmonella enterica, and Citobacter freundii (7.6% each), Citrobacter braakii (6.6%), Klebsiella pneumoniae, and Klebsiella oxytoca (5.4% each) (Table 3). The confidence level of identification for each isolate was in the range of 91–99%.
Synthesis, X-ray characterization, and in vitro biological approach of dimeric and polymeric mercury(II) complexes with α-keto stabilized sulfur ylide
Published in Journal of Coordination Chemistry, 2018
Seyyed Javad Sabounchei, Mojdeh Sadat Hashemi, Roya Karamian, Seyed Hamed Moazzami Farida, Parviz Gohari Derakhshandeh, Robert W. Gable, Kristof Van Hecke
The synthesized complexes were screened for their antibacterial activities against Escherichia coli, Salmonella typhimurium, Klebsiella oxytoca, and Shigella dysenteriae as Gram-negative bacteria and Listeria monocytogenes, Bacillus subtilis, Bacillus cereus and Staphylococcus aureus as Gram-positive bacteria. The complexes were dissolved in DMSO to a final concentration of 1 mgmL−1 and filtrated using a 0.45 µm Millipore (Burlington, MA). All complexes were carried using 10 mL of a suspension containing 1.5 × 108 bacteria mL−1 and spread on nutrient agar medium. The antibiotics Penicillin, Ampicillin, Vancomycin, and Tetracycline were used as positive reference standards, and negative controls were prepared by using DMSO. The inhibition zone diameter and the amount of swelling from the edge of each disc in the plate are given in mm.
Molecular identification and phylogenetic analysis of Bothrops insularis bacterial and fungal microbiota
Published in Journal of Toxicology and Environmental Health, Part A, 2018
Lidiane Nunes Barbosa, Rui Seabra Ferreira Jr, Priscila Luiza Mello, Hans Garcia Garces, Jéssica Luana Chechi, Tarsila Frachin, Luciana Curtolo De Barros, Sandra De Moraes Guimenes Bosco, Eduardo Bagagli, Ary Fernandes Júnior, Benedito Barraviera, Lucilene Delazari Dos Santos
Gram-negative bacteria were predominant with 32.7% belonging to the family Enterobacteriaceae (Citrobacter sp., Klebsiella pneumoniae and Klebsiella oxytoca, Morganella morganii, and Serratia marcescens and Serratia sp.). Enterobacteria are one of the most frequent bacterial groups found in snakes, including those of the genus Bothrops, isolated from the cloaca and mouth (Campagner et al. 2012; Ferreira Junior et al. 2009, 2010). The examination of intestinal microbiota of B. jararaca performed by Bastos et al. (2008) also verified the prevalence of enterobacteria, whose most frequent isolates were Salmonella (27.3%), Citrobacter (26.0%), and Escherichia (12.3%).