Screening of microorganisms producing biosurfactants from renewable substrates

Biosurfactants are one of the promising biotechnological products applied in agriculture. Their use, however, is currently far from economically viable, due to the expensive feedstock for the growth of microorganisms. The solution to this problem can be to reduce the cost of production by using organic waste as a nutrient substrate. In this study, oil-containing wastes were considered as substrates - waste frying sunflower oil and petroleum-contaminated soil. At the first stage of research, we screened native waste microorganisms capable of synthesizing biosurfactants. As a result of the study, strains with the ability to form biosurfactants were isolated. Six strains (A, B, C, D, E, F) were isolated from waste frying sunflower oil, two strains (A1, B1) were isolated from petroleum-contaminated soil. The highest yield of biosurfactants is typical for strains A and A1 - 0.429 and 0.502 mg ml-1, while the best ratio of biosurfactant mass to cell biomass is typical for strains A1 and E - 0.9 and 0.6. The most effective producer of biosurfactants turned out to be strain E with an emulsifying activity of E24 equal to 80% and a surface tension of the culture liquid of 27.1 mN m-1

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

Screening of microorganisms producing biosurfactants from renewable substrates

Biosurfactants are one of the promising biotechnological products applied in agriculture. Their use, however, is currently far from economically viable, due to the expensive feedstock for the growth of microorganisms. The solution to this problem can be to reduce the cost of production by using organic waste as a nutrient substrate. In this study, oil-containing wastes were considered as substrates - waste frying sunflower oil and petroleum-contaminated soil. At the first stage of research, we screened native waste microorganisms capable of synthesizing biosurfactants. As a result of the study, strains with the ability to form biosurfactants were isolated. Six strains (A, B, C, D, E, F) were isolated from waste frying sunflower oil, two strains (A1, B1) were isolated from petroleum-contaminated soil. The highest yield of biosurfactants is typical for strains A and A1 - 0.429 and 0.502 mg ml-1, while the best ratio of biosurfactant mass to cell biomass is typical for strains A1 and E - 0.9 and 0.6. The most effective producer of biosurfactants turned out to be strain E with an emulsifying activity of E24 equal to 80% and a surface tension of the culture liquid of 27.1 mN m-1

Characterization of biosurfactants produced by the

Biosurfactants are amphiphilic substances with a wide range of uses. Biosurfactants are being researched in various areas of biotechnology. They are especially widely used in the development of new environmentally friendly methods for increasing oil production, as well as in agriculture as an effective biocontrol agent. However, the possibility of finding strains producing biosurfactants and the efficiency of their production is a separate task for research. The aim of this work was to evaluate the dynamics of biosurfactant production by the Bacillus amyloliquefaciens VKMA B-12464 strain, as well as to evaluate its chemical nature. During the research, the resulting biosurfactant was characterized by TLC and IR spectroscopy. It has been established that the biosurfactant produced by Bacillus amyloliquefaciens belongs to lipopeptides, and its highest yield is observed on the 7th day of cultivation

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

Bioassay of Industrial Waste Pollutants

© 2007 by Taylor & Francis Group, LLC. Persistent contaminants in the environment affect human health and ecosystems. It is important to assess the risks of these pollutants for environmental policy. Ecological risk assessment (ERA) is a tool to estimate adverse effects on the environment from chemical or physical stressors. It is anticipated that ERA will be the main tool used by the U.S. Department of Energy (US DOE) to accomplish waste management [1]. Toxicity bioassays are the important line of evidence in an ERA. Recent environmental legislation and increased awareness of the risk of soil and water pollution have stimulated a demand for sensitive and rapid bioassays that use indigenous and ecologically relevant organisms to detect the early stages of pollution and monitor subsequent ecosystem change

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

Lipopeptides Produced by Bacillus mojavensis 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&minus;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