Use of biosurfactants produced by Bacillus subtilis H1 and Pseudomonas aeruginosa PAO1 as a disinfectant and plant growth stimulation

Sustainable agriculture involves the maximum use of the resource potential of the earth, with the constant renewal of the fertility of the ecosystem. One method of transition to sustainable agriculture is the use of biological control agents, which include biosurfactants. We assessed the possibility of using crude biosurfactants obtained from Bacillus subtilis H1 and Pseudomonas aeruginosa PAO1 as dressing agents for untreated wheat seeds and the presence of seed germination stimulating properties. It was shown that crude rhamnolipids obtained from Pseudomonas aeruginosa PAO1 inhibited the area occupied by fungal mycelia at a concentration of 500 mg/l. Surfactin, derived from Bacillus subtilis H1, inhibited fungal growth at a concentration of 100 mg/L. Stimulation of germination of wheat seeds by 1.9 and 2 times was determined by rhamnolipid at a concentration of 500 mg/l and surfactin at a concentration of 100 mg/l for 168 hours of germination. The use of biocontrol agents is a promising method that can improve product quality while reducing the negative impact on the environment

The abundance of health-associated bacteria is altered in PAH polluted soils-Implications for health in urban areas?

Long-term exposure to polyaromatic hydrocarbons (PAHs) has been connected to chronic human health disorders. It is also well-known that i) PAH contamination alters soil bacterial communities, ii) human microbiome is associated with environmental microbiome, and iii) alteration in the abundance of members in several bacterial phyla is associated with adverse or beneficial human health effects. We hypothesized that soil pollution by PAHs altered soil bacterial communities that had known associations with human health. The rationale behind our study was to increase understanding and potentially facilitate reconsidering factors that lead to health disorders in areas characterized by PAH contamination. Large containers filled with either spruce forest soil, pine forest soil, peat, or glacial sand were left to incubate or contaminated with creosote. Biological degradation of PAHs was monitored using GC-MS, and the bacterial community composition was analyzed using 454 pyrosequencing. Proteobacteria had higher and Actinobacteria and Bacteroidetes had lower relative abundance in creosote contaminated soils than in non-contaminated soils. Earlier studies have demonstrated that an increase in the abundance of Proteobacteria and decreased abundance of the phyla Actinobacteria and Bacteroidetes are particularly associated with adverse health outcomes and immunological disorders. Therefore, we propose that pollution-induced shifts in natural soil bacterial community, like in PAH-polluted areas, can contribute to the prevalence of chronic diseases. We encourage studies that simultaneously address the classic "adverse toxin effect" paradigm and our novel "altered environmental microbiome" hypothesis.Peer reviewe

Biosurfactants produced by the novel strain

Plant fungal diseases cause up to 15-20% and, in extreme cases, up to 60% yield loss globally. The use of chemical pesticides for the suppression of fungal plant diseases has many negative consequences for the environment. Therefore, new alternatives to suppress fungal pathogens are actively sought. In this present study, biosurfactants produced by the novel strain of Bacillus subtilis H1 were monitored for their ability to inhibit the growth of phytopathogens Fusarium oxysporum f. sp. lycopersici and Alternaria spp in in vitro and in vivo experiments. In the in vitro experiment, the treatment of tomato leaves with a biosurfactant fully inhibited the growth of F. oxysporum, and reduced the growth of Alternaria spp mycelium by 11.5 times at a concentration of 1000 mg/l. In the in vivo experiment, the use of a biosurfactant reduced the degree of damage to tomato and wheat plants, but less than in the in vitro experiment. In the case of tomato leaves infected with F. oxysporum and Alternaria spp and treated with 1000 mg/l biosurfactants, a decrease of 2.6 and 2.1 times was determined relative to infected but intreated leaves. For wheat leaves, the decrease was by 1.6 and 2.0 times, respectively. It can be concluded that biosurfactants produced by B. subtilis H1 are promising to be used for fungal pathogens biocontrol

Spatial distribution of antibiotic-resistant genes in arable lands in Russia

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Use of biosurfactants produced by

Sustainable agriculture involves the maximum use of the resource potential of the earth, with the constant renewal of the fertility of the ecosystem. One method of transition to sustainable agriculture is the use of biological control agents, which include biosurfactants. We assessed the possibility of using crude biosurfactants obtained from Bacillus subtilis H1 and Pseudomonas aeruginosa PAO1 as dressing agents for untreated wheat seeds and the presence of seed germination stimulating properties. It was shown that crude rhamnolipids obtained from Pseudomonas aeruginosa PAO1 inhibited the area occupied by fungal mycelia at a concentration of 500 mg/l. Surfactin, derived from Bacillus subtilis H1, inhibited fungal growth at a concentration of 100 mg/L. Stimulation of germination of wheat seeds by 1.9 and 2 times was determined by rhamnolipid at a concentration of 500 mg/l and surfactin at a concentration of 100 mg/l for 168 hours of germination. The use of biocontrol agents is a promising method that can improve product quality while reducing the negative impact on the environment

Biodegradation Rate of EDTA and IDS and Their Metal Complexes

Ethylenediaminetetraacetic acid (EDTA), when used as a main chelator for complex plant microfertilizers, causes many negative environmental effects; therefore, new compounds or new use of the known compounds to replace EDTA have been widely studied. In the present study, biodegradation rate, plant (Raphanus sativus) growth stimulation and ecotoxicity towards Daphnia magna and Chlorella vulgaris of iminodisuccinic acid (IDS), considered as an alternative for EDTA in agriculture, has been investigated. It was demonstrated that IDS’ biodegradation rate over 28 days was 28.1%, which is 4.5 times higher than that of EDTA. Similar to EDTA, complexation with metals led to an increase in the degradation rate by 1.8-fold. The majority of compounds were degraded within first 7 days. The GI values for IDS implemented at concentrations of 100 mg/L (both in pure form and in combination with microelements) were 2.4–2.6 times higher than those of EDTA. The ecotoxicity index EC10 of IDS was estimated to be 2.0 g/L and 5.8 g/L towards D. magna and Ch. vulgaris which are 4.1- and 10-fold higher than those for EDTA, respectively. It can be concluded that IDS is a promising agent to chelate microelements used in plant nutrition

Di- and Mono-Rhamnolipids Produced by the Pseudomonas putida PP021 Isolate Significantly Enhance the Degree of Recovery of Heavy Oil from the Romashkino Oil Field (Tatarstan, Russia)

Around the globe, only 30–50% of the amount of oil estimated to be in reservoirs (“original oil in place”) can be obtained using primary and secondary oil recovery methods. Enhanced oil recovery methods are required in the oil processing industry, and the use of microbially produced amphiphilic molecules (biosurfactants) is considered a promising efficient and environmentally friendly method. In the present study, biosurfactants produced by the Pseudomonas putida PP021 isolate were extracted and characterized, and their potential to enhance oil recovery was demonstrated. It was found that the cell-free biosurfactant-containing supernatant decreased the air–water interface tension from 74 to 28 mN m−1. Using TLC and FTIR methods, the biosurfactants produced by the isolate were classified as mono- and di-rhamnolipid mixtures. In the isolates’ genome, the genes rhlB and rhlC, encoding enzymes involved in the synthesis of mono- and di-rhamnolipids, respectively, were revealed. Both genes were expressed when the strain was cultivated on glycerol nitrate medium. As follows from the sand-packed column and core flooding simulations, biosurfactants produced by P. putida PP021 significantly enhance the degree of recovery, resulting in additional 27% and 21%, respectively

The Use of Biological Methods for Toxicity Evaluation of Wastes and Waste-Amended Soils

© 2014 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. Wastes and waste-amended soils can content different contaminants in them. Total concentrations of these contaminants can not be used for ecological risk assessment. Biological methods appeared to be necessary to evaluate the potential ecological impact. Estimation of toxicity of wasts and waste-amended soils plays an important role for decision making concerning further management of them. Nowadays, vary methods of bioindication and bio-testing based on bacteria, crustacean, protozoan, rotifer, alga, higher plant and other organisms are used. In this chapter, the most common used methods are presented

A Comparison of Microbial Contact Bioassay With Conventional Elutriate Assays for Evaluation of Wastes Hazard

The aim of this investigation was to develop a battery of bioassays - contact and elutriate tests with Bacillus pumilus, elutriate tests with Daphnia magna and Paramecium caudatum, for the assessment of the wastes\u27 toxicity. The contact test with B. pumilus was more sensitive than the elutriate test. The estimated LID10 were much higher for Daphnia and Bacillus tests than for Paramecium test. No correlation was determined between the data files of bioassays and of the chemical analysis of the waste. The procedure for classifying the wastes into the hazard classes by calculating LID10 in the Bacillus test was proposed. Copyright © 2010 Inderscience Enterprises Ltd

Lipopeptides Produced by <i>Bacillus mojavensis</i> P1709 as an Efficient Tool to Maintain Postharvest Cherry Tomato Quality and Quantity

Because of significant yield losses caused by fungal pathogens, new efficient and environmentally safe methods of pest control are needed, and amphiphilic compounds (biosurfactants) produced by many microbes are considered a good alternative. In the present study, biosurfactants produced by the rhizosphere isolate Bacillus mojavensis P1709 were assessed for their ability to protect postharvest cherry tomatoes from decay and mycotoxin contamination caused by Fusarium oxysporum f. sp. lycopersici. It was demonstrated that the genome of B. mojavensis P1709 contained the fenD and srfAA genes, which are responsible for the synthesis of compounds of the fengycin and surfactin families. APF (acid-precipitated fraction) of B. mojavensis P1709 culture medium at a concentration of 20 g L−1 inhibited pathogen radial growth on agar plates by 93%, and T-2 and HT-2 mycotoxin production by 98%, after 5 days of cultivation. APF also suppressed fungal growth in the in vivo test on cherry tomato fruits by 93% and 25% on the 2nd and 7th days of incubation, respectively. The results obtained demonstrate that biosurfactants produced by B. mojavensis P1709 are an efficient tool for protecting postharvest cherry tomatoes from fungal mold decay and mycotoxin contamination