China
Africa
Explore chapters and articles related to this topic
Microbial Bioremediation of Petroleum Hydrocarbons in Moderate to Extreme Environments and Application of “omics” Techniques to Evaluate Bioremediation Approaches and Efficiency
Published in Gunjan Mukherjee, Sunny Dhiman, Waste Management, 2023
Maricy Raquel Lindenbah Bonfá, Rodrigo Matheus Pereira, Francine Amaral Piubeli, Lucia Regina Durrant
Psychrophilic bacteria usually occur in extremely cold environments such as at the poles. Some of them are widely used in bioremediation processes in these environments (Chaudhary and Kim 2019). In one example, soil samples were collected from a deactivated oil well on Ellesmere Island in Canada’s High Arctic (Ferguson et al. 2020), from a region that had experienced a crude oil spill in 1972 and was isolated ever since. After metagenomic analysis, the authors noticed a significantly different microbial composition when comparing contaminated soil samples with soil samples adjacent to the bottom, which were not contaminated Among the bacteria found, two genera stood out Rhodanobacter (Alphaproteobacteria) which was found consistently in contaminated soils, and members of the genus Sphingomona (Gammaproteobacteria). The researchers suggest that the more abundant presence of Sphingomonas in samples contaminated with oil indicates that the presence of degraders is possible. Previous research has reported hydrocarbon degradation by this genus (Zhao et al. 2017, Canul-Chan et al. 2018).
Fate and Behavior of Endocrine Disrupters in Wastewater Treatment Processes
Published in Jason W. Birkett, John N. Lester, Endocrine Disrupters in Wastewater and Sludge Treatment Processes, 2002
The biodegradation of NP has been observed by Sphingomonas sp.79Pseudomonas sp. was also present although it is thought it provided nutrients for the growth of Sphingomonas sp. rather than degrading 4NP itself. More than 95% of the NP was degraded within 10 days and no aromatic compounds were detected suggesting that the phenolic part was also degraded. The main degradation products were alcohols, the major one being nonanol. Different isomers of NP were used. This resulted in the formation of different isomers of nonanol, implying that the alcohols were derived from the alkyl group. Candida maltosa is a species of yeast that has been found to degrade 4NP to produce 4-acetylphenol.80 The yeast was isolated from sludge at a textile industry treatment plant and used 4NP as its sole carbon source.
Algal Biofuel: A Promising Alternative for Fossil Fuel
Published in Maniruzzaman A. Aziz, Khairul Anuar Kassim, Wan Azelee Wan Abu Bakar, Aminaton Marto, Syed Anuar Faua’ad Syed Muhammad, Fossil Free Fuels, 2019
Hoofar Shokravi, Zahra Shokravi, Maniruzzaman A. Aziz, Hooman Shokravi
Green macroalgae contains glucans as the main carbohydrate component that is easily fermentable. Unlike green macroalgae, the existing carbohydrate component in red macroalgae and brown macroalgae, i.e., alginate and mannitol—3,6-anhydro-L-galactose—are not easily fermentable [43]. Finding or engineering the appropriate microbes to be capable of converting all types of carbohydrates into biofuels is one of the challenges of microbiological biotechnologies in recent years. The harvesting of brown algae is twofold that of red algae, whereas the green algae have the least value among all macroalgae and the lowest harvest [44]. Hence several research studies are conducted to enhance the hydrocarbon utilization of brown and red macroalgae through microbiological biotechnologies. There is a limited number of microbes for the modification of alginate for biofuel production. Hence, extensive studies are conducted to use bioengineering tools to modify the structure of microbes toward facilitating the production of algal biofuels. Bacterium Sphingomonas sp. A1 is one of the well-known microbes used to assimilate alginate. However, this bacterium is unable to assimilate mannitol to extract the carbohydrates [45]. Takeda et al. [46] introduced two gene encoded version of Sphingomonas sp. A1 to optimize the condition of algal biofuel production. Bioengineered E. coli is another example that was very advantageous and improved 40% in the production of biofuel from macroalgae compared to its plasmid-based counterpart [47,48]. S. cerevisiae is a unicellular eukaryote yeast with a well-characterized genetic system. Hence it has none of the genes required to assimilate alginate and mannitol. Bioengineered S. cerevisiae is able to metabolize alginate and mannitol for biofuel production [49].
The role of hygrodynamic resistance compared to biofilm formation in helping pathogenic bacteria dominate air-conditioning units recovered from odour problems
Published in Environmental Technology, 2023
Wing Lam Chan, Liwen Luo, Haoxiang Wu
Sphingomonas spp. are commonly found in hospitals and water, and its presence in ACUs has also been reported [21,22]. S. paucimobilis has been isolated from environments with limited nutrients; e.g. ultrapure water system in hospitals, indicating its oligotrophic feature [21]. Due to the installation of filters, nutrient supply for odour production was reduced, which may lead to the dominance of this oligotroph.
Influence of different phytoremediation on soil microbial diversity and community composition in saline-alkaline land
Published in International Journal of Phytoremediation, 2022
Fengxia Li, Yongzhong Guo, Zhangjun Wang, Yangxiu Mu
In our study, MX, YK and HMC treatments increased the bacterial diversity, while YM treatments increased the fungal diversity, and YK and HMC treatments decreased the fungal diversity, which indicated there were differences in the microbial diversity of soil in different plants. Proteobacteria, a dominant phylum, is the largest group of bacteria in our study, and this phylum includes many nitrogen fixing bacteria (such as rhizobia) (Spain et al. 2009). Sphingomonas, a kind of rich new microbial resources, is the most important dominant bacterial genus, which is the biomarkers of MY treatments. Additionally, Sphingomonas can survive in the environment with limited nutrition, showing the characteristics of denitrification and non-symbiotic nitrogen fixation, so it may participate in the nitrogen cycle (Hu et al. 2016). Moreover, Sphingomonas can also be used for the biodegradation of aromatic compounds, so it plays an important role in environmental pollution (Aulestia et al. 2021), which may be the reason why this bacterium can become the dominant bacterium in saline-alkali soil (Figure 2a). In this study, we found that MX and YM treatments significantly increased the abundance of Sphingomonas, which may be that the two plants can enrich nitrogen fixing bacteria in soil and further improve soil nutrition and quality, which may be related to the increase of TN and AN in MX and YM treatments. More importantly, Lysobacter can secrete a variety of antibiotics, enzymes and bioactive substances, inhibit other bacteria and regulate plant diseases (Hu et al. 2016), of which the agricultural relevance is becoming increasingly apparent, especially in the ecologically important microbial communities associated with soil and plants (Islam et al. 2005). In our study, MX and YM treatments significantly increased the abundance of Lysobacter, indicating that MX and YM are the best choose in saline-alkali soil restoration.
Bacterial distribution in long-term dioxin-contaminated soil in Vietnam and novel dioxin degrading bacteria isolated from Phu Cat airbase
Published in Soil and Sediment Contamination: An International Journal, 2023
Kien Cuong Pham, Thi Tam Thu Nguyen, Van Hoang Nguyen, Anh T.N. Dao
The unknown group was the most abundant in genus taxonomic level, which occupied approximately 50% in all tested soil, 47.8%; 48.6%, and 57.8% for PC1; PC2, and BH, respectively. The large proportion of unknowns suggested that there is high biological potential in the contaminated soil that needs to be revealed. The species richness in samples was evaluated by several alpha diversity indices. The result indicated the estimated number of species in an assemblage was close to the observed numbers, and the species richness of BH was much higher than that of PC1 and PC2. In other words, bacterial diversity in Bien Hoa dioxin-contaminated soil was greater than in soil from Phu Cat airbase (Figure 4). Bacterial genus structures in contaminated soil in Bien Hoa and Phu Cat were different in the numbers of genera, the predominant one and the proportion of intersection genera (Sup Figure 2). In BH soil, the predominant genera were Anaeromyxobacter, Nocardioides, Solirubrobacter, Marmoricola, and Gaiella. However, in Phu Cat soil, a similar bacterial structure has been revealed in both contaminated and non-contaminated one, but the relative abundances of each genus differed from each other. The most abundant in PC1 and PC2 was Geodermatophilus followed by Conexibacter, Sinomonas, Acidothermus, Bryobacter, and Sphingomonas. Among those genera, Sphingomonas has shown great potential in dioxin degradation, both on laboratory and on pilot scales; the genus properly plays an important factor in bioremediation of the contaminated site in the future (Wittich et al. 1992; Colquhoun, Hartmann, and Halden 2012; Mishra et al. 2021; Saibu et al. 2020 W.-Y. Chen et al. 2016). For example, Sphingomonas sp. RW1 and Sphingomonas wittichii RW1 degrade dibenzo-p-dioxin (DD), dibenzofuran (DF), and chlorinated DDs/DFs by angular deoxygenation (Nam, Kim, and Schmidt 2006; Wittich et al. 1992). Next, Sphingomonas genus has shown a correlation between the increase in relative abundance with the decrease of 2,3,7,8-tetrachlodibenzo-p-dioxin in enrichment cultures (Nguyen and * Ha Thi Cam Dang, Ton That Huu Dat 3, Bernd W. Brandt 4, Wilfred F. M. Röling 1†, Abraham Brouwer 5, and and Rob J. M. van Spanning 2022).