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Biosorbents Based on Carbonized Apricot Stones and Rice Busk
Published in Zulkhair A. Mansurov, Carbon Nanomaterials in Biomedicine and the Environment, 2020
Arkhat S. Kurmanbekov, Azhar A. Zhubanova, Zulkhair A. Mansurov
The study on physicochemical properties of carbonized sorbents obtained by carbonization of apricot stones and rice husk, the development of biosorbents on their basis by the attachment of Rhodotorula glutinis var. glutinis, Pseudomonas aeruginosa, Pseudomonas mendocina cells onto the sorbents. The results obtained in this study allow drawing the following conclusions: The studies on the immobilization of Rhodotorula glutinis var. glutinis, Pseudomonas aeruginosa, and Pseudomonas mendocina cell onto the surface of the initial and carbonized materials on the basis of rice husk and apricot stones have revealed that the largest number of cells attached onto the sorbents carbonized at 650°C. It was shown that the rate of hydrophobicity of microorganisms exerts a significant influence on the interaction of cells with these materials.It was determined by the method of thermal desorption that the specific surface of carbonized sorbents on the basis of rice husk was increased by 25% after immobilization of microbial cells onto it. The data obtained from this study allow us to recommend this biosorbent for practical use.
Application of Genetic Engineering to the Field of Bioremediation
Published in Donald L. Wise, Debra J. Trantolo, Remediation of Hazardous Waste Contaminated Soils, 2018
Alan R. Harker, Youngjun Kim, Udayakumar Matrubutham
Several monooxygenase enzymes that act on aromatic rings have been reported to degrade TCE. We have previously reported that TCE is effectively degraded by the phenol pathway encoded on the chromosome of Alcaligenes eutrophus JMP 134 and enzymes related to 2.4-dichlorophenoxyacetic acid (2,4-D) degradation encoded on the plasmid pJP4 in JMP 134.14 The para-acting toluene monooxygenase15 in Pseudomonas mendocina and the meta-acting toluene monooxygenase16 in Pseudomonas pickettii PKOl are also enzymes capable of oxidizing TCE. Toluene dioxygenase of Pseudomonas putida F1, which is also known to effect TCE degradation,12 was found to have the ability to hydroxylate phenol, suggesting that this alternative mechanism may be operating on TCE.17 Shields et al. have suggested that TCE degradation is associated with a single enzyme, which is responsible for the hydroxylation of toluene, cresol, and phenol in Pseudomonas cepacia G4.18
Genetic Strategies for Strain Improvement
Published in Daphne L. Stoner, Biotechnology for the Treatment of Hazardous Waste, 2017
There are several examples of the use of hybrid promoter and operator sequences for regulated expression of recombinant catabolic enzymes. Different application needs have been met using genetic engineering techniques. The toluene monooxygenase enzyme system from Pseudomonas mendocina has been cloned into several plasmids that provide regulated expression in Escherichia coli. This altered regulation provides distinct advantages over wild-type expression. The enzyme system in the wild-type microorganism is unstable in the absence of a natural inducer such as toluene (Figure 1). Enzyme activity is rapidly lost from the culture if toluene is removed. Activity of the enzyme system in the recombinant organism is significantly improved. Altered regulation of toluene monooxygenase is beneficial in the degradation of nongrowth substrates such as trichloroethylene (TCE) by this enzyme system.33 Because synthesis of this enzyme system requires the presence of toluene in the natural isolate, degradation of TCE and other chlorinated ethenes is subject to competitive inhibition by toluene. Both the chlorinated ethene and the natural substrate compete for the same active site on toluene monooxygenase. The recombinant microorganism does not require toluene, so there is no competitive inhibition effects against TCE, and as a consequence, more efficient and extensive degradation is observed. In this example, the recombinant microorganisms do not degrade either toluene or TCE any faster than the wild-type organism does, but the altered regulation permits synthesis of the enzyme in the absence of interfering substrates and allows more efficient and extensive degradation to proceed.
Bioenergy recovery associated with treatment of actual meat industry wastewater in blue green algal biocathode based microbial fuel cell: Experimental and modeling study
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Safa H. Fadhil, Zainab Z. Ismail
Activated sludge was freshly collected from a local domestic wastewater treatment facility. The obtained activated sludge was exploited a source for mixed bacterial cells. The biocatalyst samples were stored in plastic containers under anaerobic conditions at 4°C until used. The characterization of the sludge revealed that the predominant types of bacteria were Pseudomonas mendocina sp. and Bacillus sp.