RESUMO
Petroleum hydrocarbons pose a significant threat to human health and the environment. Biochar has increasingly been utilized for soil remediation. This study investigated the potential of biochar immobilization using Serratia sp. F4 OR414381 for the remediation of petroleum-contaminated soil through a pot experiment conducted over 90 days. The treatments in this study, denoted as IMs (maize straw biochar-immobilized Serratia sp. F4), degraded 82.5% of the total petroleum hydrocarbons (TPH), 59.23% of the aromatic, and 90.1% of the saturated hydrocarbon fractions in the loess soils. During remediation, the soil pH values decreased from 8.76 to 7.33, and the oxidation-reduction potential (ORP) increased from 156 to 229 mV. The treatment-maintained soil nutrients of the IMs were 138.94 mg/kg of NO3- -N and 92.47 mg/kg of available phosphorus (AP), as well as 11.29% of moisture content. The activities of soil dehydrogenase (SDHA) and catalase (CAT) respectively increased by 14% and 15 times compared to the CK treatment. Three key petroleum hydrocarbon degradation genes, including CYP450, AJ025, and xylX were upregulated following IMs treatment. Microbial community analysis revealed that a substantial microbial population of 1.01E+ 09 cells/g soil and oil-degrading bacteria such as Salinimicrobium, Saccharibacteria_genera_incertae_sedis, and Brevundimonas were the dominant genera in IMs treatment. This suggests that the biochar immobilized on Serratia sp. F4 OR414381 improves soil physicochemical properties and enhances interactions among microbial populations, presenting a promising and environmentally friendly approach for the stable and efficient remediation of petroleum-contaminated loess soil.
Assuntos
Biodegradação Ambiental , Carvão Vegetal , Hidrocarbonetos , Petróleo , Serratia , Microbiologia do Solo , Poluentes do Solo , Serratia/metabolismo , Serratia/genética , Poluentes do Solo/metabolismo , Carvão Vegetal/química , Petróleo/metabolismo , Hidrocarbonetos/metabolismo , Poluição por Petróleo , Solo/químicaRESUMO
Bacterial pigments are potential substitute of chemical photosensitizer for dye-sensitized solar cell (DSSC) due to its non-toxic property and cost-effective production from microbial fermentation. Serratia nematodiphila YO1 was isolated from waterfall in Malaysia and identified using 16S ribosomal RNA. Characterization of the red pigment produced by the bacteria has confirmed the pigment as prodigiosin. Prodigiosin was produced from the fermentation of the bacteria in the presence of different oil substrates. Palm oil exhibited the best performance of cell growth and equivalent prodigiosin yield compared to olive oil and peanut oil. Prodigiosin produced with palm oil supplementation was 93â¯mg/l compared to 7.8â¯mg/l produced without supplementation, which recorded 11.9 times improvement. Specific growth rate of the cells improved 1.4 times when palm oil was supplemented in the medium. The prodigiosin pigment produced showed comparable performance as a DSSC sensitizer by displaying an open circuit voltage of 336.1â¯mV and a maximum short circuit current of 0.098â¯mV/cm2. This study stands a novelty in proving that the production of prodigiosin is favorable in the presence of palm oil substrate with high saturated fat content, which has not been studied before. This is also among the first bacterial prodigiosin tested as photosensitizer for DSSC application.
Assuntos
Fontes de Energia Bioelétrica , Reatores Biológicos/microbiologia , Óleo de Palmeira/farmacologia , Prodigiosina , Serratia , Meios de Cultura/química , Meios de Cultura/farmacologia , Concentração de Íons de Hidrogênio , Processos Fotoquímicos , Prodigiosina/análise , Prodigiosina/metabolismo , Serratia/efeitos dos fármacos , Serratia/metabolismoRESUMO
It has become increasingly apparent that the environmental microorganisms residing in uranium (U) enriched sites offer the possibility of understanding the biological mechanisms catalyzing the processes important for uranium bioremediation. Here, we present the results of uranium biomineralization over a wide pH range by a metal tolerant Serratia sp. strain OT II 7 isolated from the subsurface soil of a U ore deposit at Domiasiat in India. The Serratia cells actively expressed acid and alkaline phosphatase enzymes which hydrolyzed differential amounts of phosphate from an organophosphate substrate in the presence of uranium between pH 5 to 9. These cells precipitated â¼91% uranium from aqueous solutions supplemented with 1 mM uranyl nitrate at pH 5 within 120 h. More rapid precipitation was observed at pH 7 and 9 wherein the cells removed â¼93-94% of uranium from solutions containing 1 mM uranyl carbonate within 24 h. The aqueous uranyl speciation prevalent under the studied pH conditions influenced the localization of crystalline uranyl phosphate precipitates, which in turn, impacted the cell viability to a great extent. Furthermore, the cells tolerated up to â¼1.6 kGy 60Co gamma radiation and their uranium precipitation abilities at pH 5, 7 and 9 were uncompromised even after exposure to a high dose of ionizing radiation. Overall, this study establishes the ecological adaptation of a natural strain like Serratia in a uranium enriched environment and corroborates its contribution towards uranium immobilization in contaminated subsurfaces through the formation of stable uranyl phosphate minerals over a wide pH range.
Assuntos
Ácidos/farmacologia , Álcalis/farmacologia , Biodegradação Ambiental , Biomineralização , Poluentes Radioativos/farmacologia , Serratia/metabolismo , Urânio/metabolismo , Precipitação Química , Concentração de Íons de Hidrogênio , Fosfatos/metabolismo , Serratia/efeitos dos fármacos , Serratia/efeitos da radiaçãoRESUMO
Plant growth promoting endophytic bacteria (PGPB) isolated from Brassica napus were inoculated in two cultivars of Helianthus tuberosus (VR and D19) growing on sand supplemented with 0.1 mM Cd or 1 mM Zn. Plant growth, concentrations of metals and thiobarbituric acid (TBA) reactive compounds were determined. Colonization of roots of H. tuberosus D19 by Pseudomonas sp. 262 was evaluated using confocal laser scanning microscopy. Pseudomonas sp. 228, Serratia sp. 246 and Pseudomonas sp. 262 significantly enhanced growth of H. tuberosus D19 exposed to Cd or Zn. Pseudomonas sp. 228 significantly increased Cd concentrations in roots. Serratia sp. 246, and Pseudomonas sp. 256 and 228 resulted in significantly decreased contents of TBA reactive compounds in roots of Zn exposed D19 plants. Growth improvement and decrease of metal-induced stress were more pronounced in D19 than in VR. Pseudomonas sp. 262-green fluorescent protein (GFP) colonized the root epidermis/exodermis and also inside root hairs, indicating that an endophytic interaction was established. H. tuberosus D19 inoculated with Pseudomonas sp. 228, Serratia sp. 246 and Pseudomonas sp. 262 holds promise for sustainable biomass production in combination with phytoremediation on Cd and Zn contaminated soils.
Assuntos
Cádmio/metabolismo , Endófitos/metabolismo , Pseudomonas/metabolismo , Serratia/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Zinco/metabolismo , Biodegradação Ambiental , Brassica napus/microbiologia , Cádmio/toxicidade , Endófitos/efeitos dos fármacos , Endófitos/crescimento & desenvolvimento , Genes Reporter , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Helianthus/efeitos dos fármacos , Helianthus/microbiologia , Microscopia Confocal , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/microbiologia , Pseudomonas/efeitos dos fármacos , Pseudomonas/crescimento & desenvolvimento , Serratia/efeitos dos fármacos , Serratia/crescimento & desenvolvimento , Poluentes do Solo/toxicidade , Tiobarbitúricos/metabolismo , Zinco/toxicidadeRESUMO
Synthetic fatliquors are useful as a fatliquoring agent, flotation agent and emulsifying agent in a wide range of industrial applications such as leather, pharmacy and farm chemicals. These fatliquors remain recalcitrant to natural biota in existing treatment plants. In the present study, the isolated microaerophilic Serratia sp. HA1 strain CSMB3 is capable of utilizing structurally different fatliquors as the sole substrate for their growth under microaerobic conditions. Degradation of vegetable fatliquors was observed from 95 to 97% in terms of lipids, with the production of lipase at 72 h. Degradation of synthetic fatliquors was observed in terms of chemical oxygen demand from 85% to a minimum of 25%. It is in the order of sulfited/sulfated fatliquors > sulfochlorinated fatliquors > chlorinated fatliquors. A thin layer chromatography chromatogram confirmed the degradation of non polar fatliquor to polar compounds. Production of the red pigment prodigiosin in synthetic fatliquors enhanced the growth of the isolate. Fourier transform infrared spectroscopy (FTIR) confirmed the bioremediation of sulfochlorinated fatliquor into lipids and fatty acids and gas chromatography-mass spectrometry (GC-MS) results confirmed that alcohols and esters are the final end products. Thus the isolated strain CSMB3 may be used in the treatment of wastewaters containing vegetable and synthetic fatliquors.
Assuntos
Emulsões/metabolismo , Lipídeos/química , Aerobiose , Biodegradação Ambiental , Análise da Demanda Biológica de Oxigênio , Cromatografia em Camada Fina , Cromatografia Gasosa-Espectrometria de Massas , Lipase/metabolismo , Óleos de Plantas/química , Prodigiosina/química , Serratia/crescimento & desenvolvimento , Serratia/isolamento & purificação , Serratia/metabolismo , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
BACKGROUND: Obesity and Type 2 diabetes have reached epidemic status worldwide. Wild lowbush blueberry (Vaccinium angustifolium Aiton) is a plant of the North American Aboriginal traditional pharmacopeia with antidiabetic potential, especially when it is fermented with Serratia vaccinii. METHODS: A phytochemical fractionation scheme was used to identify potential bioactive compounds as confirmed by HPLC retention times and UV-Vis spectra. 3 T3-L1 cells were differentiated for 7 days with either Normal Blueberry Extract (NBE), Fermented Blueberry Extract (FBE/F1), seven fractions and four pure compounds. Triglyceride content was measured. Examination of selected intracellular signalling components (p-Akt, p-AMPK) and transcriptional factors (SREBP-1c and PPARγ) was carried out by Western blot analysis. RESULTS: The inhibitory effect of FBE/F1 on adipocyte triglyceride accumulation was attributed to total phenolic (F2) and chlorogenic acid enriched (F3-2) fractions that both inhibited by 75%. Pure compounds catechol (CAT) and chlorogenic acid (CA) also inhibited adipogenesis by 70%. Treatment with NBE, F1, F3-2, CAT and CA decreased p-AKT, whereas p-AMPK tended to increase with F1. The expression of SREBP1-c was not significantly modulated. In contrast, PPARγ decreased in all experimental groups that inhibited adipogenesis. CONCLUSIONS: These results demonstrate that fermented blueberry extract contains compounds with anti-adipogenic activity, which can serve to standardize nutraceutical preparations from fermented blueberry juice and to develop novel compounds with anti-obesity properties.
Assuntos
Adipócitos/efeitos dos fármacos , Adipogenia/efeitos dos fármacos , Mirtilos Azuis (Planta)/química , Mirtilos Azuis (Planta)/microbiologia , Extratos Vegetais/farmacologia , Serratia/metabolismo , Células 3T3-L1 , Adipócitos/citologia , Adipócitos/metabolismo , Animais , Fermentação , Camundongos , PPAR gama/genética , PPAR gama/metabolismo , Extratos Vegetais/química , Extratos Vegetais/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismoRESUMO
Vermicomposting is a dependable waste recycling technology which greatly augments N and P levels mainly through microbial action. This paper aims to identify efficient N-fixing (NFB) and P-solubilizing (PSB) bacteria from earthworm intestines. Various combinations of vegetable market waste, rice straw, and cowdung were fed to two earthworm species (Eisenia fetida and Perionyx excavatus). Total organic C decreased, pH shifted towards neutrality, and NPK availability, and microbial (NFB, PSB, and total bacteria) population increased remarkably during vermicomposting with E. fetida. Therefore, 45 NFB and 34 PSB strains isolated from Eisenia gut were initially screened, their inter-dominance assessed, and 8 prolific strains were identified through 16SrRNA sequencing. Interestingly, two novel N-fixing strains of Kluyvera ascorbata emerged as an efficient biofertilizer candidate. Moreover, both N-fixing and P-solubilizing strains of Serratia and Bacillus were isolated from earthworm gut. All the isolated strains significantly improved soil health and facilitated crop growth as compared to commercial biofertilizers.
Assuntos
Oligoquetos/microbiologia , Oryza , Solo , Verduras , Gerenciamento de Resíduos/métodos , Animais , Microbioma Gastrointestinal/genética , Intestinos/microbiologia , Kluyvera/genética , Kluyvera/isolamento & purificação , Kluyvera/metabolismo , Esterco/microbiologia , Fixação de Nitrogênio , Fósforo/química , Fósforo/metabolismo , Brotos de Planta , RNA Ribossômico 16S , Reciclagem , Serratia/genética , Serratia/isolamento & purificação , Serratia/metabolismoRESUMO
Stimulating the microbially-mediated precipitation of uranium biominerals may be used to treat groundwater contamination at nuclear sites. The majority of studies to date have focussed on the reductive precipitation of uranium as U(IV) by U(VI)- and Fe(III)-reducing bacteria such as Geobacter and Shewanella species, although other mechanisms of uranium removal from solution can occur, including the precipitation of uranyl phosphates via bacterial phosphatase activity. Here we present the results of uranium biomineralisation experiments using an isolate of Serratia obtained from a sediment sample representative of the Sellafield nuclear site, UK. When supplied with glycerol phosphate, this Serratia strain was able to precipitate 1 mM of soluble U(VI) as uranyl phosphate minerals from the autunite group, under anaerobic and fermentative conditions. Under phosphate-limited anaerobic conditions and with glycerol as the electron donor, non-growing Serratia cells could precipitate 0.5 mM of uranium supplied as soluble U(VI), via reduction to nano-crystalline U(IV) uraninite. Some evidence for the reduction of solid phase uranyl(VI) phosphate was also observed. This study highlights the potential for Serratia and related species to play a role in the bioremediation of uranium contamination, via a range of different metabolic pathways, dependent on culturing or in situ conditions.
Assuntos
Serratia/metabolismo , Poluentes Radioativos do Solo/metabolismo , Compostos de Urânio/metabolismo , Anaerobiose , Biodegradação Ambiental , Precipitação Química , Cloretos/metabolismo , Meios de Cultura , Fumaratos/farmacologia , Sedimentos Geológicos/microbiologia , Glicerol/farmacologia , Microscopia Eletrônica , Minerais/isolamento & purificação , Minerais/metabolismo , Nanopartículas , Oxirredução , Fosfatos/isolamento & purificação , Fosfatos/metabolismo , Serratia/isolamento & purificação , Microbiologia do Solo , Solubilidade , Urânio/metabolismo , Compostos de Urânio/isolamento & purificação , Difração de Raios XRESUMO
Serratia sp. ATCC 39006 (S39006) is a Gram-negative bacterium that is virulent in plant (potato) and animal (Caenorhabditis elegans) models. It produces two secondary metabolite antibiotics, a prodigiosin and a carbapenem, and the exoenzymes, pectate lyase and cellulase. A complex regulatory network that includes quorum sensing (QS) controls production of prodigiosin. While many aspects of the regulation of the metabolites and exoenzymes are well understood, the potential role in this network of the RNA chaperone Hfq and dependent small regulatory RNAs has not been characterized. Hfq is an RNA chaperone involved in post-transcriptional regulation that plays a key role in stress response and virulence in diverse bacterial species. To explore whether Hfq-dependent processes might contribute to the regulation of antibiotic production we constructed an S39006 Δhfq mutant. Production of prodigiosin and carbapenem was abolished in this mutant strain, while production of the QS signalling molecule, butanoyl homoserine lactone (BHL), was unaffected. Using transcriptional fusions, we found that Hfq regulates the QS response regulators, SmaR and CarR. Additionally, exoenzyme production and swimming motility were decreased in a Δhfq mutant, and virulence was attenuated in potato and C. elegans models. These results suggest that an Hfq-dependent pathway is involved in the regulation of virulence and secondary metabolite production in S39006.
Assuntos
Antibacterianos/biossíntese , Proteínas de Bactérias/metabolismo , Carbapenêmicos/biossíntese , Chaperonas Moleculares/metabolismo , Prodigiosina/biossíntese , Serratia/metabolismo , 4-Butirolactona/análogos & derivados , 4-Butirolactona/biossíntese , Animais , Proteínas de Bactérias/genética , Caenorhabditis elegans/microbiologia , Regulação Bacteriana da Expressão Gênica , Chaperonas Moleculares/genética , Mutação , Percepção de Quorum , RNA Bacteriano/metabolismo , Serratia/genética , Serratia/patogenicidade , Solanum tuberosum/microbiologia , Transcrição Gênica , VirulênciaRESUMO
A growing body of evidence supports the therapeutic effects of blueberry in neurodegenerative disorders. Biotransformation of blueberry juice by Serratia vaccinii bacteria increases its phenolic content and antioxidant activity. In neuronal cell culture, biotransformed blueberry juice (BJ) significantly increased the activity of antioxidant enzymes, namely catalase and superoxide dismutase. Moreover, BJ protected neurons against H2O2-induced cell death in a dose-dependent manner. This associated with the upregulation of mitogen-activated protein kinase (MAPK) family enzymes p38 and c-Jun N-terminal kinase (JNK) activation, as well as with the protection of extracellular signal-regulated kinase (ERK1/2) and MAPK/ERK kinase (MEK1/2) activity loss induced by H2O2. The present studies demonstrate that BJ can protect neurons against oxidative stress possibly by increasing antioxidant enzyme activities and activating p38- and JNK-dependent survival pathways while blocking MEK1/2- and ERK1/2-mediated cell death. Thus, BJ may represent a novel approach to prevent and to treat neurodegenerative disorders, and it may represent a source of novel therapeutic agents against these diseases.
Assuntos
Antioxidantes/farmacologia , Mirtilos Azuis (Planta) , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Neurônios/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Preparações de Plantas/farmacologia , Serratia/metabolismo , Animais , Antioxidantes/metabolismo , Biotransformação , Mirtilos Azuis (Planta)/metabolismo , Mirtilos Azuis (Planta)/microbiologia , Catalase/metabolismo , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Fermentação , Peróxido de Hidrogênio , Camundongos , Fármacos Neuroprotetores/farmacologia , Preparações de Plantas/metabolismo , Transdução de Sinais/efeitos dos fármacos , Superóxido Dismutase/metabolismo , Regulação para CimaRESUMO
An enrichment culture technique was used for the isolation of bacteria responsible for biodegradation of diazinon in soil. Three bacterial strains were screened and identified by MIDI-FAME profiling as Serratia liquefaciens, Serratia marcescens and Pseudomonas sp. All isolates were able to grow in mineral salt medium (MSM) supplemented with diazinon (50 mgL(-1)) as a sole carbon source, and within 14d 80-92% of the initial dose of insecticide was degraded by the isolates and their consortium. Degradation of diazinon was accelerated when MSM was supplemented with glucose. However, this process was linked with the decrease of pH values, after glucose utilization. Studies on biodegradation in sterilized soil showed that isolates and their consortium exhibited efficient degradation of insecticide (100mg kg(-1) soil) with a rate constant of 0.032-0.085d(-1), and DT(50) for diazinon was ranged from 11.5d to 24.5d. In contrast, degradation of insecticide in non-sterilized soil, non-supplemented earlier with diazinon, was characterized by a rate constant of 0.014d(-1) and the 7-d lag phase, during which only 2% of applied dose was degraded. The results suggested a strong correlation between microbial activity and chemical processes during diazinon degradation. Moreover, isolated bacterial strains may have potential for use in bioremediation of diazinon-contaminated soils.
Assuntos
Diazinon/metabolismo , Inseticidas/metabolismo , Pseudomonas/metabolismo , Serratia/metabolismo , Biodegradação Ambiental , Diazinon/análise , Inseticidas/análise , Cinética , Pseudomonas/isolamento & purificação , Serratia/isolamento & purificação , Microbiologia do SoloRESUMO
We assessed the biodegradation of a typical oily sludge waste (PB401) in Mexico using several regimes of indigenous microbial consortium and relevant bioremediation strategies in slurry-phase system. Abiotic loss of total petroleum hydrocarbons (TPH) in the PB401 was insignificant, and degradation rates under the various treatment conditions ranged between 666.9 and 2168.7 mg kg(-1) day(-1) over a 15 days reaction period, while viable cell count peaked at between log(10)5.7 and log(10)7.4 cfu g(-1). Biostimulation with a commercial fertilizer resulted in 24% biodegradation of the TPH in the oily waste and a corresponding peak cell density of log(10)7.4 cfu g(-1). Addition of non-indigenous adapted consortium did not appear to enhance the removal of TPH from the oily waste. It would appear that the complexities of the components of the alkylaromatic fraction of the waste limited biodegradation rate even in a slurry system.
Assuntos
Bactérias/metabolismo , Petróleo/metabolismo , Esgotos/microbiologia , Bacillus/crescimento & desenvolvimento , Bacillus/metabolismo , Bactérias/crescimento & desenvolvimento , Biodegradação Ambiental , Reatores Biológicos/microbiologia , Concentração de Íons de Hidrogênio , Resíduos Industriais , Cinética , Pseudomonas/crescimento & desenvolvimento , Pseudomonas/metabolismo , Eliminação de Resíduos/instrumentação , Eliminação de Resíduos/métodos , Serratia/crescimento & desenvolvimento , Serratia/metabolismo , Esgotos/análise , Esgotos/química , Microbiologia do Solo , TemperaturaRESUMO
AIMS: To investigate the biodegrading ability and cometabolism of synthetic pyrethroid (SP) utilizing bacteria in cultures with various minerals and carbon sources. METHODS AND RESULTS: Previously isolated SP-degrading Pseudomonas sp. and Serratia sp. were used in cultures containing either flumethrin SP or cypermethrin SP formulations. The culture media consisted of either (i) water only, (ii) water and sucrose, (iii) mineral broth or (iv) mineral broth and sucrose. The growth of both organisms was greatest in the mineral broth and sucrose medium, but the growth-limiting factor for Pseudomonas sp. strain Circle was the mineral content whereas for Serratia sp. strain White it was the carbon substrate. CONCLUSION: The greatest extent of degradation of both SP-based compounds occurred with Pseudomonas sp. strain Circle but was dependant on the medium. SIGNIFICANCE AND IMPACT OF THE STUDY: This investigation could lead to the development of a relatively inexpensive medium supplement to enhance the microbial biodegradation of undesirable compounds, either in situ or ex situ. In this particular case, for the biodegradation of SPs used in sheep dip.
Assuntos
Carbono/metabolismo , Inseticidas/metabolismo , Minerais/metabolismo , Pseudomonas/metabolismo , Piretrinas/metabolismo , Serratia/metabolismo , Biodegradação Ambiental , Meios de Cultura , Concentração de Íons de Hidrogênio , Pseudomonas/crescimento & desenvolvimento , Serratia/crescimento & desenvolvimento , Sacarose/metabolismo , Tensão SuperficialRESUMO
A screening strategy was developed to assess the potential of plant-associated bacteria to control diseases caused by Rhizoctonia solani Kühn. About 434 already characterized antagonistic bacterial strains isolated from diverse plant species and microenvironments were evaluated for biocontrol and plant growth promotion by a hierarchical combination of assays. Analyzing in vitro antagonism towards different Rhizoctonia isolates resulted in a selection of 20 potential biocontrol agents. The strains were characterized by their antagonistic mechanisms in vitro as well as their production of the plant growth hormone indole-3-acetic acid. The plant growth promoting effect by antagonistic bacteria was determined using a microtiter plate assay on the basis of lettuce seedlings. Lettuce and sugar beet as host plant were included in the biocontrol experiments in which the antagonistic effect of 17 bacterial isolates could be confirmed in vivo. Sequencing of the 16S rDNA gene and (or) fatty acid methyl ester gas chromatography was used to identify the antagonistic isolates. Molecular fingerprints of isolates obtained by BOX-polymerase chain reaction were compared to avoid further investigation with genetically very similar strains and to obtain unique molecular fingerprints for quality control and patent licensing. According to our strategy, an assessment scheme was developed and four interesting biological control agents, Pseudomonas reactans B3, Pseudomonas fluorescens B1, Serratia plymuthica B4, and Serratia odorifera B6, were found. While S. plymuthica B4 was the best candidate to biologically control Rhizoctonia in lettuce, P. reactans B3 was the best candidate to suppress the pathogen in sugar beet.