Characterization of biosurfactant produced by Pseudoxanthomonas sp. PNK-04 and its application in bioremediation

Nayak, Anand S.; Vijaykumar, M.H.; Karegoudar, T. B.

doi:10.1016/j.ibiod.2008.07.003

Cited by 143 publications

(53 citation statements)

References 20 publications

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“…Numerous non-Pseudomonas URPB, "uncommon"-RLs producing bacteria have also been reported, including both Gram (-), like Pseudoxanthomonas sp. PNK-04 [52], Acinetobacter calcoaceticus, Enterobacter hormaechei, Pantoea stewartii, and E. asburiae [53], and Gram (+) bacteria [54][55][56]. Notably, some of the RLs producing bacteria are potential pathogens, such as E. hormaechei [57] and E. asburiae [58].…”

Section: Discussionmentioning

confidence: 99%

Rhamnolipids, Microbial Virulence Factors, in Alzheimer’s Disease

Andreadou

Pantazaki

Daniilidou

et al. 2017

JAD

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Abstract. Alzheimer's disease (AD) has been attributed to chronic bacterial infections. The recognition of human microbiota as a substantial contributor to health and disease is relatively recent and growing. During evolution, mammals live in a symbiotic state with myriads of microorganisms that survive at a diversity of tissue micro-surroundings. Microbes produce a plethora of secretory products [amyloids, lipopolysaccharides, virulence factors rhamnolipids (RLs), toxins, and a great number of neuroactive compounds]. The contribution of infectious microbial components to the pathophysiology of the human central nervous system including AD is considered potentially substantial, but the involvement of the RLs has never been reported. Here, RLs were isolated from serum and identified through various conventional methods including the colorimetric orcinol method, thin-layer chromatography, attenuated total reflection Fourier transform infrared (ATR-FTIR), and dot blot using antibodies against RLs. Dot blot demonstrated elevated RL levels in sera of AD patients compared to controls (p = 0.014). Moreover, ELISA showed similarly elevated RL levels in cerebrospinal fluid of both AD (0.188 versus 0.080) (p = 0.04) and mild cognitive impairment (0.188 versus 0.129) (p = 0.088) patients compared to healthy, and are wellcorrelated with the AD stages severity assessed using the Mini-Mental State Examination. These results provide conclusive evidence for the newly-reported implication of RLs in AD, adding it to the list of bacterial components, opening new avenues for AD investigation. Moreover, they strengthen and vindicate the divergence of research toward the exploration of bacterial involvement in AD generation and progression.

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Section: Discussionmentioning

confidence: 99%

Rhamnolipids, Microbial Virulence Factors, in Alzheimer’s Disease

Andreadou

Pantazaki

Daniilidou

et al. 2017

JAD

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“…However, a nonionic surfactant of Tween-80 with a low CMC of 13 mg/mL (Nayak et al, 2009) showed no inhibition of M. circinelloides CCTCC M210113 in agreement with our observations (data not shown), but, in turn, stimulated growth at a high concentration of 840 mg/mL (Lubbehusen et al, 2003). Hence, the surface activity of fungicides should not be the sole factor for illustrating antifungal activity, and the specific interactions between surfactants and the targeted membranes of fungi might also play a role (Abalos et al, 2001;Costa et al, 2010).…”

Section: Discussionmentioning

confidence: 99%

Antifungal activity of rhamnolipids against dimorphic fungi

Sha

Meng

2016

J. Gen. Appl. Microbiol.

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In this paper, rhamnolipids are investigated, for the first time, for their feasibility for inhibiting dimorphic fungi. Rhamnolipids were found to effectively inhibit a dimorphic fungus isolated from tomato plants which was identified as Mucor circinelloides according to characterizations by morphologies as well as 28S rDNA sequences. Rhamnolipids markedly reduced growth of this fungus in both the yeast-like form and the filamentous form. Such an inhibitive effect was similarly obtained with Verticillium dahliae, a representative member of dimorphic fungi, confirming the effectiveness of rhamnolipids in the two growth forms of dimorphic fungi. Interestingly, rhamnolipids showed a greater inhibitive function in the case of the pathogenic growth mode of dimorphic fungi, such as the mycelium growth for M. circinelloides and the yeast-like growth for V. dahliae, than their non-pathogenic modes. The use of rhamnolipids might greatly reduce the frequently-reported drugresistance to the common anti-fungal agents by deterring the possible switch between the two modes of dimorphic fungi. Overall, rhamnolipids as environment-friendly biocontrol agents have a potential use in protecting plants from dimorphic fungi infections, and could also offer guidance toward future research into controlling dimorphic disease infection in humans.

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“…Measuring the emulsifying activity of the culture broth during different stages of growth showed that activity was highest at the end of the exponential growth phase and stationary phase. Nayak et al [29] found that in the initial 48 h the production of rhamnolipid was low, but that after 120 h levels increased and reached 280 mg 1 -1 , clearly showing that to the production of biosurfactant is growth associated. Both Pseudomonas species studied here were shown to have high emulsification activity (up to 86% and 61%), Bacillus species had 66% activity, while Nocardiacyria cigeorgici showed 53% emulsification activity.…”

Section: Emulsification Activity Of Bacterial Isolatesmentioning

confidence: 99%

Isolation of Indigenous Hydrocarbon Transforming Bacteria from Oil Contaminated Soils in Libya: Selection for Use as Potential Inocula for Soil Bioremediation

Hakima¹,

Singleton²

2017

IJEBB

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The Libyan oil industry has left a significant legacy of contamination and methods are required to remediate oil-contaminated soils in the area. In this work hydrocarbon utilizing microorganisms were isolated and identified from contaminated soil samples obtained from an oil Refinery (Zawia, Libya). After initial screening of eleven isolates capable of growth on hexadecane, the five most promising hydrocarbon-utilizing bacteria were isolated and tested for biosurfactant production and emulsification activity. They were identified (using 16S rRNA sequence analysis) as Pseudomonas putida, Pseudomonas species, Betaproteobacterium, Actinomyces species, and Bacillus species. Among the five species tested, Pseudomonas putida showed superior performance in terms of growth on hydrocarbons (1.0×10 10 CFU (ml)), E24 emulsifying activity (86%) and ability to transform hydrocarbons in pure culture. Interestingly, gas chromatographic analysis of crude oil treated with P. putida showed a decrease in heavy hydrocarbon fractions demonstrating a clear potential for this microbe to be used as a soil inoculant in bioremediation.

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Characterization of biosurfactant produced by Pseudoxanthomonas sp. PNK-04 and its application in bioremediation

Cited by 143 publications

References 20 publications

Rhamnolipids, Microbial Virulence Factors, in Alzheimer’s Disease

Rhamnolipids, Microbial Virulence Factors, in Alzheimer’s Disease

Antifungal activity of rhamnolipids against dimorphic fungi

Isolation of Indigenous Hydrocarbon Transforming Bacteria from Oil Contaminated Soils in Libya: Selection for Use as Potential Inocula for Soil Bioremediation

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