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

Over twenty years farmland reforestation decreases fungal diversity of soils, but stimulates the return of ectomycorrhizal fungal communities

Although soil-inhabiting fungi can affect tree health and biomass production in managed and pristine forests, little is known about the sensitivity of the plant-fungal associations to long-term changes in land use. We aimed to investigate how reforestation of farmlands change soil characteristics and affected the recovery of soil fungal functional guilds. We examined edaphic conditions and fungal communities (Illumina Sequencing) in three land-use types: primary forests (PF), secondary forests (SF, established over two decades ago) and active farmlands during May, July and September in Wuying, China. Edaphic conditions and general fungal communities varied with land-use. Interestingly, overall fungal diversity was higher in soils at the farmland than at the forested sites, possibly as a result of recurring disturbances (tilling) allowing competitive release as described by the intermediate disturbance hypothesis. Although ectomycorrhizal fungal diversity and richness were marginally higher in PF than in SF, the latter still hosted surprisingly diverse and abundant ectomycorrhizal fungal communities. Reforestation largely restored fungal communities that were still in transition, as their composition in SF was distinct from that in PF. Our results highlight the ability of fungi grown in previously strongly managed agricultural land to rapidly respond to reforestation and thus provide support for forest trees.Peer reviewe

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

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

Antifungal potential of biosurfactants produced by strains of Bacillus mojavensis PS17 against pathogens of the genera Fusarium and Verticillium

Phytopathogenic fungi cause significant damage to agriculture, reducing or destroying the crop. There are several ways to control fungal diseases, such as the use of disease-resistant plant varieties, organic farming, and the use of fungicides. One of the methods of combating phytopathogens is the use of biological products, one of which is biosurfactants. Biosurfactants are surfactants produced in the course of life. They are able to reduce fungal growth and increase plant disease resistance, improve plant growth and yield, and act as adjuvants to improve wetting and solubility of fertilizers. In the course of this work, the fungicidal activity of biosurfactants formed by Bacillus mojavensis PS17 was assessed against pathogens of the genera Fusarium and Verticillium. It has been established that the biosurfactant is able to reduce the coverage area of Fusarium and Verticillium fungi in in vitro experiments by 39 and 43%. Thus, it can be concluded that the biosurfactant produced by Bacillus mojavensis PS17 has antifungal activity

Effects of Natural Rhamnolipid Mixture on Dioleoylphosphatidylcholine Model Membrane Depending on Method of Preparation and Sterol Content

Rhamnolipids as biosurfactants have a potentially wide range of applications, for example, as “green” surfactants or components of drug delivery systems, which is associated with the features of their interaction with cell membranes. However, as noted in the literature, those kind of features have not been sufficiently studied now. This paper presents a study of the interaction of a natural mixture of rhamnolipids produced by bacteria of the rhizosphere zone of plants Pseudomonas aeruginosa with model membranes—liposomes based on dioleoylphosphatidylcholine (DOPC), depending on the method of their preparation and the content of sterols—ergosterol, cholesterol, lanosterol. Liposomes with rhamnolipids were prepared by two protocols: with film method from a mixture of DOPC and rhamnolipids; with film method from DOPC and injection of water solution of rhamnolipids. Joint analysis of the data of 31P NMR spectroscopy and ATR-FTIR spectroscopy showed that in the presence of rhamnolipids, the mobility of the head group of the DOPC phospholipid increases, the conformational disorder of the hydrophobic tail increases, and the degree of hydration of the C=O and P=O groups of the phospholipid decreases. It can be assumed that, when prepared from a mixture, rhamnolipids are incorporated into the membrane in the form of clusters and are located closer to the middle of the bilayer; while when prepared by injection, rhamnolipid molecules migrate into the membrane in the form of individual molecules and are located closer to the head part of phospholipids. The sterol composition of the model membrane also affects the interaction of rhamnolipids with the membrane. Here it is worth noting the possible presence of type of interaction between rhamnolipids and ergosterol differ from other investigated sterols, due to which rhamnolipid molecules are embedded in the area where ergosterol is located

Antifungal potential of biosurfactants produced by strains of

Phytopathogenic fungi cause significant damage to agriculture, reducing or destroying the crop. There are several ways to control fungal diseases, such as the use of disease-resistant plant varieties, organic farming, and the use of fungicides. One of the methods of combating phytopathogens is the use of biological products, one of which is biosurfactants. Biosurfactants are surfactants produced in the course of life. They are able to reduce fungal growth and increase plant disease resistance, improve plant growth and yield, and act as adjuvants to improve wetting and solubility of fertilizers. In the course of this work, the fungicidal activity of biosurfactants formed by Bacillus mojavensis PS17 was assessed against pathogens of the genera Fusarium and Verticillium. It has been established that the biosurfactant is able to reduce the coverage area of Fusarium and Verticillium fungi in in vitro experiments by 39 and 43%. Thus, it can be concluded that the biosurfactant produced by Bacillus mojavensis PS17 has antifungal activity

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

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