Bacterial community structure analysis of sludge from Taozi lake and isolation of an efficient 17ß-Estradiol (E2) degrading strain Sphingobacterium sp. GEMB-CSS-01.

Environmental challenges arising from organic pollutants pose a significant problem for modern societies. Efficient microbial resources for the degradation of these pollutants are highly valuable. In this study, the bacterial community structure of sludge samples from Taozi Lake (polluted by urban sewage) was studied using 16S rRNA sequencing. The bacterial phyla Proteobacteria, Bacteroidetes, and Chloroflexi, which are potentially important in organic matter degradation by previous studies, were identified as the predominant phyla in our samples, with relative abundances of 48.5%, 8.3%, and 6.6%, respectively. Additionally, the FAPROTAX and co-occurrence network analysis suggested that the core microbial populations in the samples may be closely associated with organic matter metabolism. Subsequently, sludge samples from Taozi Lake were subjected to enrichment cultivation to isolate organic pollutant-degrading microorganisms. The strain Sphingobacterium sp. GEMB-CSS-01, tolerant to sulfanilamide, was successfully isolated. Subsequent investigations demonstrated that Sphingobacterium sp. GEMB-CSS-01 efficiently degraded the endocrine-disrupting compound 17ß-Estradiol (E2). It achieved degradation efficiencies of 80.0% and 53.5% for E2 concentrations of 10 mg/L and 20 mg/L, respectively, within 10 days. Notably, despite a reduction in degradation efficiency, Sphingobacterium sp. GEMB-CSS-01 retained its ability to degrade E2 even in the presence of sulfanilamide concentrations ranging from 50 to 200 mg/L. The findings of this research identify potential microbial resources for environmental bioremediation, and concurrently provide valuable information about the microbial community structure and patterns within Taozi Lake.

Racemization of the substrate and product by serine palmitoyltransferase from Sphingobacterium multivorum yields two enantiomers of the product from d-serine.

Serine palmitoyltransferase (SPT) catalyzes the pyridoxal-5'-phosphate (PLP)-dependent decarboxylative condensation of l-serine and palmitoyl-CoA to form 3-ketodihydrosphingosine (KDS). Although SPT was shown to synthesize corresponding products from amino acids other than l-serine, it is still arguable whether SPT catalyzes the reaction with d-serine, which is a question of biological importance. Using high substrate and enzyme concentrations, KDS was detected after the incubation of SPT from Sphingobacterium multivorum with d-serine and palmitoyl-CoA. Furthermore, the KDS comprised equal amounts of 2S and 2R isomers. 1H-NMR study showed a slow hydrogen-deuterium exchange at Cα of serine mediated by SPT. We further confirmed that SPT catalyzed the racemization of serine. The rate of the KDS formation from d-serine was comparable to those for the α-hydrogen exchange and the racemization reaction. The structure of the d-serine-soaked crystal (1.65 Å resolution) showed a distinct electron density of the PLP-l-serine aldimine, interpreted as the racemized product trapped in the active site. The structure of the α-methyl-d-serine-soaked crystal (1.70 Å resolution) showed the PLP-α-methyl-d-serine aldimine, mimicking the d-serine-SPT complex prior to racemization. Based on these enzymological and structural analyses, the synthesis of KDS from d-serine was explained as the result of the slow racemization to l-serine, followed by the reaction with palmitoyl-CoA, and SPT would not catalyze the direct condensation between d-serine and palmitoyl-CoA. It was also shown that the S. multivorum SPT catalyzed the racemization of the product KDS, which would explain the presence of (2R)-KDS in the reaction products.

Biodegradation of penicillin G sodium by Sphingobacterium sp. SQW1: Performance, degradation mechanism, and key enzymes.

Biodegradation is an efficient and cost-effective approach to remove residual penicillin G sodium (PGNa) from the environment. In this study, the effective PGNa-degrading strain SQW1 (Sphingobacterium sp.) was screened from contaminated soil using enrichment technique. The effects of critical operational parameters on PGNa degradation by strain SQW1 were systematically investigated, and these parameters were optimized by response surface methodology to maximize PGNa degradation. Comparative experiments found the extracellular enzyme to completely degrade PGNa within 60 min. Combined with whole genome sequencing of strain SQW1 and LC-MS analysis of degradation products, penicillin acylase and ß-lactamase were identified as critical enzymes for PGNa biodegradation. Moreover, three degradation pathways were postulated, including ß-lactam hydrolysis, penicillin acylase hydrolysis, decarboxylation, desulfurization, demethylation, oxidative dehydrogenation, hydroxyl reduction, and demethylation reactions. The toxicity of PGNa biodegradation intermediates was assessed using paper diffusion method, ECOSAR, and TEST software, which showed that the biodegradation products had low toxicity. This study is the first to describe PGNa-degrading bacteria and detailed degradation mechanisms, which will provide new insights into the PGNa biodegradation.

Desulfurization properties, pathways, and potential applications of two novel and efficient chemolithotrophic sulfur-oxidizing strains of Pseudomonas sp. GHWS3 and Sphingobacterium sp. GHWS5.

With the accelerated modernization of agriculture and industry, sulfides have been released into the environment as a by-products of various production processes. Elevated levels of sulfide pose a threat to organisms' health and disrupt ecosystem equilibrium. This study successfully isolated two highly efficient sulfur-oxidizing strains, namely Pseudomonas aeruginosa GHWS3 and Sphingobacterium sp. GHWS5. Neither strain exhibited hemolytic activity or pathogenicity. Additionally, GHWS3 inhibited the common aquaculture pathogen Vibrio anguillarum, while GHWS5 exhibited inhibitory effects against Vibrio harveyi. GHWS3 and GHWS5 demonstrated effective removal of sulfide under the following conditions: temperature range of 20-40 °C, pH level of 4.5-8.5, salinity range of 0-50‰, C/N ratio of 5-15, and sulfide concentration of 20-200 mg/L. By amplifying the key functional genes of the sulfur-oxidizing Sox and rDsr systems in both GHWS3 and GHWS5 strains, potential desulfurization pathways were analyzed. Furthermore, both strains displayed high efficiency in removing sulfides from actual aquaculture pond substrate mixtures. The findings of this study provide two promising candidate strains for sulfides removal from farm tailwater, industrial wastewater, and domestic wastewater.

Multi-omic profiling of a novel activated sludge strain Sphingobacterium sp. WM1 reveals the mechanism of tetracycline biodegradation and its merits of potential application.

As an emerging pollutant, the antibiotic tetracycline (TC) has been consistently detected in wastewater and activated sludge. Biodegradation represents a potentially crucial pathway to dissipate TC contamination. However, few efficient TC-degrading bacteria have been isolated and a comprehensive understanding of the molecular mechanisms underlying TC degradation is still lacking. In this study, a novel TC-degrading bacterium, designated as Sphingobacterium sp. WM1, was successfully isolated from activated sludge. Strain WM1 exhibited a remarkable performance in degrading 50 mg/L TC within 1 day under co-metabolic conditions. Genomic analysis of the strain WM1 unveiled the presence of three functional tetX genes. Unraveling the complex molecular mechanisms, transcriptome analysis highlighted the role of upregulated transmembrane transport and accelerated electron transport in facilitating TC degradation. Proteomics confirmed the up-regulation of proteins involved in cellular biosynthesis/metabolism and ribosomal processes. Crucially, the tetX gene-encoding protein showed a significant upregulation, indicating its role in TC degradation. Heterologous expression of the tetX gene resulted in TC dissipation from an initial 51.9 mg/L to 4.2 mg/L within 24 h. The degradation pathway encompassed TC hydroxylation, transforming into TP461 and subsequent metabolites, which effectively depleted TC's inhibitory activity. Notably, the tetX genes in strain WM1 showed limited potential for horizontal gene transfer. Collectively, strain WM1's potent TC degradation capacity signals a promise for enhancing TC clean-up strategies.

Identification and characterization of a deaminoneuraminic acid (Kdn)-specific aldolase from Sphingobacterium species.

Sialic acid (Sia) is a group of acidic sugars with a 9-carbon backbone, and classified into 3 species based on the substituent group at C5 position: N-acetylneuraminic acid (Neu5Ac), N-glycolylneuraminic acid (Neu5Gc), and deaminoneuraminic acid (Kdn). In Escherichia coli, the sialate aldolase or N-acetylneuraminate aldolase (NanA) is known to catabolize these Sia species into pyruvate and the corresponding 6-carbon mannose derivatives. However, in bacteria, very little is known about the catabolism of Kdn, compared with Neu5Ac. In this study, we found a novel Kdn-specific aldolase (Kdn-aldolase), which can exclusively degrade Kdn, but not Neu5Ac or Neu5Gc, from Sphingobacterium sp., which was previously isolated from a Kdn-assimilating bacterium. Kdn-aldolase had the optimal pH and temperature at 7.0-8.0 and 50 °C, respectively. It also had the synthetic activity of Kdn from pyruvate and mannose. Site-specific mutagenesis revealed that N50 residue was important for the Kdn-specific reaction. Existence of the Kdn-aldolase suggests that Kdn-specific metabolism may play a specialized role in some bacteria.

Characterization of Sphingobacterium sp. Ab3 Lipase and Its Coexpression with LEA Peptides.

Sphingobacterium sp. is a yellowish Gram-negative bacterium that is usually characterized by high concentrations of sphingophospholipids as lipid components. As microbial enzymes have been in high demand in industrial fields in the past few decades, this study hopes to provide significant information on lipase activities of Sphingobacterium sp., since limited studies have been conducted on the Sphingobacterium sp. lipase. A microbe from one collected Artic soil sample, ARC4, was identified as psychrotolerant Sphingobacterium sp., and it could grow in temperatures ranging from 0°C to 24°C. The expression of Sphingobacterium sp. lipase was successfully performed through an efficient approach of utilizing mutated group 3 late embryogenesis abundant (G3LEA) proteins developed from Polypedilum vanderplanki. Purified enzyme was characterized using a few parameters, such as temperature, pH, metal ion cofactors, organic solvents, and detergents. The expressed enzyme is reported to be cold adapted and has the capability to work efficiently under neutral pH (pH 5.0 to 7.0), cofactors like Na+ ion, and the water-like solvent methanol. Addition of nonionic detergents greatly enhanced the activity of purified enzyme. IMPORTANCE The mechanism of action of LEA proteins has remained unknown to many; in this study we reveal their presence and improved protein expression due to the molecular shielding effect reported by others. This paper should be regarded as a useful example of using such proteins to influence an existing expression system to produce difficult-to-express proteins.

Metabolomics reveals the mechanism of tetracycline biodegradation by a Sphingobacterium mizutaii S121.

Contamination by tetracycline residues has adverse influences on the environment and is considered a pressing issue. Biodegradation is regarded as a promising way to treat tetracycline residues in the environment. Here, strain Sphingobacterium mizutaii S121, which could degrade 20 mg/L tetracycline completely within 5 days, was isolated from contaminated soil. The characteristics of tetracycline degradation by strain S121 were investigated under various culture conditions. Response surface methodology was used to predict the maximum tetracycline degradation ratio, which can be obtained under the following conditions: 31.36 °C, pH of 7.15, and inoculum volume of 5.5% (v/v). Furthermore, extracellular tetracycline biodegradation products and intracellular metabolic pathways of S121 were detected by ultraperformance liquid chromatography-quadrupole-time-of-flight-mass spectrometry (UPLC-Q-TOF-MS) and UHPLC-quadrupole electrospray (QE)-MS, respectively. The results identified eight possible degradation products, and three putative degradation pathways were proposed. In addition, exposure to tetracycline produced significant influences on metabolic pathways such as pyrimidine, purine, taurine and hypotaurine metabolism and lysine degradation. Consequently, the intracellular metabolic pathway response of S121 in the presence of tetracycline was proposed. These findings are presented for the first time, which will facilitate a comprehensive understanding of the mechanism of tetracycline degradation. Moreover, strain S121 can be a promising bacterium for tetracycline bioremediation.

Cyanide removal from aqueous environment by resting cells and PTFE immobilized cells of Sphingobacterium spp.

Microbial detoxification of cyanide offered an inexpensive, safe, and viable alternative to physiochemical processes for the treatment of cyanide in industrial effluents or contaminated sites. This study involved isolation of novel strain with high resistance against cyanide toxicity and able to degrade the cyanide radical. The strain was isolated from rocky area and identified as Sphingobacterium multivorium using 16S ribosomal RNA. Resting pregrown cells were used in simple reaction mixture to avoid the complication associated with the media. One-gram fresh weight of this bacteria was able to remove 98.5% from 1.5 g/L cyanide which is a unique result. Factor affecting the biochemical process such as pH, temperature, agitation, glucose concentration was examined. The optimum conditions were, pH 6-7, 30-40°C, and 100-150 rpm shaking speed and 0.25% glucose. Furthermore, the cells were used after immobilization in polytetrafluoroethylene (PTFE) polymer. The PTFE is very safe carrier and the cells withstand the entrapment process and were able to remove 92% (1 g/L cyanide). The immobilized cells were used for six successive cycles with about 50% removal efficiency. The storage life extended to 14 days. No previous work studied the cyanide removal by Sphingobacterium spp. The strain showed good applicable characters.

[Expression of polyphosphate kinase from Sphingobacterium siyangensis and its application in ATP regeneration system].

Polyphosphate kinase plays an important role in the catalytic synthesis of ATP in vitro. In order to find a polyphosphate kinase that can efficiently synthesize ATP using short-chain polyphosphate (polyP) as substrate, the polyphosphate kinase 2 (PPK2) from Sphingobacterium siyangensis was cloned and expressed in Escherichia coli BL21(DE3). As an enzyme for ATP regeneration, PPK2 was used in combination with l-amino acid ligase (YwfE) to produce l-alanyl-l-glutamine (Ala-Gln). The length of ppk2 of S. siyangensis is 810 bp, encoding 270 amino acids. The SDS-PAGE showed that PPK2 was expressed correctly and its molecular weight was 29.7 kDa as expected. The reaction conditions of PPK2 were optimized. PPK2 could maintain good activity in the range of 22-42 ℃ and pH 7-10. The highest enzyme activity was observed at 37 ℃, pH 7, 30 mmol/L magnesium ion (Mg2+), 5 mmol/L ADP and 10 mmol/L sodium hexametaphosphate, and the yield of ATP reached 60% of the theoretical value in 0.5 hours at this condition. When used in combination with YwfE to produce Ala-Gln, the PPK2 showed a good applicability as an ATP regeneration system, and the effect was similar to that of direct addition of ATP. The PPK2 from S. siyangensis shows good performance in a wide range of temperature and pH, synthesizes ATP with cheap and readily available short chain polyP as substrate. The PPK2 thus provides a new enzyme source for ATP dependent catalytic reaction system.

Expression of polyphosphate kinase from Sphingobacterium siyangensis and its application in ATP regeneration system / 生物工程学报

Polyphosphate kinase plays an important role in the catalytic synthesis of ATP in vitro. In order to find a polyphosphate kinase that can efficiently synthesize ATP using short-chain polyphosphate (polyP) as substrate, the polyphosphate kinase 2 (PPK2) from Sphingobacterium siyangensis was cloned and expressed in Escherichia coli BL21(DE3). As an enzyme for ATP regeneration, PPK2 was used in combination with l-amino acid ligase (YwfE) to produce l-alanyl-l-glutamine (Ala-Gln). The length of ppk2 of S. siyangensis is 810 bp, encoding 270 amino acids. The SDS-PAGE showed that PPK2 was expressed correctly and its molecular weight was 29.7 kDa as expected. The reaction conditions of PPK2 were optimized. PPK2 could maintain good activity in the range of 22-42 ℃ and pH 7-10. The highest enzyme activity was observed at 37 ℃, pH 7, 30 mmol/L magnesium ion (Mg2+), 5 mmol/L ADP and 10 mmol/L sodium hexametaphosphate, and the yield of ATP reached 60% of the theoretical value in 0.5 hours at this condition. When used in combination with YwfE to produce Ala-Gln, the PPK2 showed a good applicability as an ATP regeneration system, and the effect was similar to that of direct addition of ATP. The PPK2 from S. siyangensis shows good performance in a wide range of temperature and pH, synthesizes ATP with cheap and readily available short chain polyP as substrate. The PPK2 thus provides a new enzyme source for ATP dependent catalytic reaction system.

Sphingobacterium phlebotomi sp. nov., a new member of family Sphingobacteriaceae isolated from sand fly rearing substrate.

A Gram-stain-negative, rod-shaped, non-motile, non-spore-forming, aerobic bacterium, designated type strain SSI9T, was isolated from sand fly (Phlebotomus papatasi Scopoli; Diptera: Psychodidae) rearing substrate and subjected to polyphasic taxonomic analysis. Strain SSI9T contained phosphatidylethanolamine as a major polar lipid, MK-7 as the predominant quinone, and C16 : 1ω6c/C16 : 1ω7c, iso-C15 : 0, iso-C17 : 0 3-OH and C16 : 0 as the major cellular fatty acids. Phylogenetic analysis based on 16S rRNA gene sequences revealed that SSI9T represents a member of the genus Sphingobacterium, of the family Sphingobacteriaceae sharing 96.5-88.0 % sequence similarity with other species of the genus Sphingobacterium. The results of multilocus sequence analysis using the concatenated sequences of the housekeeping genes recA, rplC and groL indicated that SSI9T formed a separate branch in the genus Sphingobacterium. The genome of SSI9T is 5 197 142 bp with a DNA G+C content of 41.8 mol% and encodes 4395 predicted coding sequences, 49 tRNAs, and three complete rRNAs and two partial rRNAs. SSI9T could be distinguished from other species of the genus Sphingobacterium with validly published names by several phenotypic, chemotaxonomic and genomic characteristics. On the basis of the results of this polyphasic taxonomic analysis, the bacterial isolate represents a novel species within the genus Sphingobacterium, for which the name Sphingobacterium phlebotomi sp. nov. is proposed. The type strain is SSI9T (=ATCC TSD-210T=LMG 31664T=NRRL B-65603T).

An alkali-tolerant phospholipase D from Sphingobacterium thalpophilum 2015: Gene cloning, overproduction and characterization.

The phospholipase pl-S.t gene of Sphingobacterium thalpophilum 2015 was cloned and the gene sequence was submitted to NCBI with Accession Number KX674735.1. The phylogenetic analysis showed that this PL-S.t was clustered to phospholipase D (PLD). As far as we know, the PL-S.t with a molecular mass of 22.5 kDa is the lowest of the currently purified bacterial PLDs, which belongs to a non-HKD PLD enzyme. This PL-S.t was resistant to a wide range of alkali pHs (7.5-9.0) after 1 h incubation, retaining more than 90% of its maximum activity. The PL-S.t activity can be enhanced by Ni2+, Co2+ and Mn2+. This PL-S.t has only one cysteine residue and fewer negatively-charged amino acids (AAs). The hydrogen bonds network was found around the cystein108, which may be beneficial to the stability and activity of PL-S.t in Ni2+ solution. This study has laid the foundation for further research on the molecular mechanism of the catalytic characteristics of low molecular weight alkalic PLD from S. thalpophilum 2015.

Biodegradation of organophosphorus pesticide chlorpyrifos by Sphingobacterium sp. C1B, a psychrotolerant bacterium isolated from apple orchard in Himachal Pradesh of India.

A psychrotolerant Sphingobacterium sp. was isolated from the apple orchard situated in the Kufri region of Shimla, Himachal Pradesh, India using an enrichment culture technique having chlorpyrifos (CP) as the sole source of carbon and energy. Based on biochemical characterization and 16S rRNA analysis, the strain was identified as Sphingobacterium sp. C1B. The bacterium C1B was able to degrade chlorpyrifos ≥ 42 ppm and ≥ 36 ppm within 14 days at 20 °C and 15 °C, respectively. The strain was also able to degrade chlorpyrifos ≤ 35 ppm at 28 °C within 14 days. The enzyme organophosphorus hydrolase might be responsible for the initial degradation of CP by the strain C1B. Based on the HPLC and GCMS analysis, a probable degradation pathway has been proposed, which followed the path from chlorpyrifos to 3,5,6-trichloro-2-pyridinol to benzene, 1,3-bis (1,1-dimethylethyl) and then entered into the TCA cycle. Our current study revealed that the bacterium C1B was found to be a useful strain for the degradation of pesticide chlorpyrifos in the cold climatic environment.

Characterization of different alginate lyases for dissolving Pseudomonas aeruginosa biofilms.

Aggregates of Pseudomonas aeruginosa form a protective barrier against antibiotics and the immune system. These barriers, known as biofilms, are associated with several infectious diseases. One of the main components of these biofilms is alginate, a homo- and hetero-polysaccharide that consists of ß-D-mannuronate (M) and α-L-guluronate (G) units. Alginate lyases degrade this sugar and have been proposed as biotherapeutic agents to dissolve P. aeruginosa biofilms. However, there are contradictory reports in the literature regarding the efficacy of alginate lyases against biofilms and their synergistic effect with antibiotics. We found that most positive reports used a commercial crude extract from Flavobacterium multivorum as the alginate lyase source. By using anion exchange chromatography coupled to nano LC MS/MS, we identified two distinct enzymes in this extract, one has both polyM and polyG (polyM/G) degradation activities and it is similar in sequence to a broad-spectrum alginate lyase from Flavobacterium sp. S20 (Alg2A). The other enzyme has only polyG activity and it is similar in sequence to AlyA1 from Zobellia galactanivorans. By characterizing both of these enzymes together with three recombinant alginate lyases (a polyM, a polyG and a polyM/G), we showed that only enzymes with polyM/G activity such as Alg2A and A1-II' (alginate lyase from Sphingomonas sp.) are effective in dissolving biofilms. Furthermore, both activities are required to have a synergistic effect with antibiotics.

Co-biodegradation studies of naphthalene and phenanthrene using bacterial consortium.

Degradation studies of phenanthrene and naphthalene as a mixture was carried out using a developed bacterial consortium. The isolates used in consortium were identified as Chryseobacterium sp., Sphingobacterium sp., Stenotrophomonas sp., Agromyces sp. and Pseudomonas sp. Limited work is done on genus Agromyces in degradation studies of PAHs. Catechol production was detected using Arnow's assay suggested that the pathway used for degradation is the meta-cleavage pathway. Results showed that Tween 80, as a surfactant, had maximum effect on the growth of isolates during PAH degradation. This suggests that use of Tween 80 as a surfactant enhanced the uptake of PAH by bacterial isolates during degradation. The study further revealed that, bacterial consortium was successfully utilized in the treatment of water contaminated with PAH in a laboratory-scale biofilm bioreactor. The bacterial consortium was able to degrade 99.9% of naphthalene and 92.9% of phenanthrene as a mixture at a high concentration of 2000 mg/L within 6 days. Further scaling up of the biofilm bioreactor can prove beneficial in large scale treatment of PAH contaminated water. This study showed promising results and these bacterial strains can be used as potential tools for bioremediation of PAH in contaminated sites.

Effect of transient pH variation on microbial activity and physical characteristics of aerobic granules treating 4-chlorophenol.

Chlorophenols are inhibitory compounds that can be biodegraded by aerobic granules in discontinuous processes. Many industrial wastewaters are characterized by transient pH variation over time. These pH changes could affect the overall granule structure and microbial activity during the chlorophenol biodegradation. The objective of this research was to evaluate the effects of transient pH variation on the specific degradation rate (q), granule integrity coefficient (IC), and size in sequencing batch reactors treating 4-chlorophenol (4-CP). First, aerobic granules were acclimated for efficient 4-CP degradation (>99%). The acclimated granules consisted of 55.7% of the phyla Proteobacteria and 40.6% of Bacteroidetes. The main bacteria belong to the order Sphingobacteriales (24%), as well as Amaricoccus, Acidovorax, Shinella, Rhizobium, and Flavobacterium, some of which are new genera reported in acclimated granules degrading 4-CP. Then, pH changes were applied to the acclimated aerobic granules, observing that acid pHs decreased to a greater extent the specific degradation rate (67% to 99%) than basic pHs (34% to 80%). These pH changes caused the granule disaggregation but with lower effects on the IC. The effects of pH change were mainly on the microbial activity more than the physical characteristics of aerobic granules degrading 4-CP.

Endophytic bacteria promote growth of the medicinal legume Clitoria ternatea L. by chemotactic activity.

Part of the native root nodule endophytic microflora referring to members of the genera Proteobacteria and Sphingobacteria were used to test their bioefficacy as seed biopriming. These were quantified for their plant growth promoting (PGP) attributes such as IAA production, P and K-solubilization and ACC deaminase production. Results showed that significantly highest IAA was produced by E. hormaechi RCT10. The highest P-solubilization was observed with S. maltophila RCT31 it was solubilizing all the substrate tri-calcium phosphate, di-calcium phosphate, and zinc phosphate. Significantly highest K-solubilization was observed with S. maltophila RCT31 followed by E. turicensis RCT5. However, the maximum zinc solubilization was reported with S. maltophila RCT31 followed by E. turicensis RCT5. The maximum ACC deaminase was quantified in the bacterium. Results revealed that the E. hormaechi RCT10 utilized seed leechates most effectively while root exudates were maximally utilized by S. maltophila RCT31. The pots experiment proves that S. maltophila RCT31 was the most effective bacterium and it was replication vis-à-vis field experiment. In particular, S. maltophila RCT31 holds strong potential to be possibly used as a bioformulation for the medicinal legume, as an economical and eco-friendly alternative to agrochemicals.

Defining the eco-enzymological role of the fungal strain Coniochaeta sp. 2T2.1 in a tripartite lignocellulolytic microbial consortium.

Coniochaeta species are versatile ascomycetes that have great capacity to deconstruct lignocellulose. Here, we explore the transcriptome of Coniochaeta sp. strain 2T2.1 from wheat straw-driven cultures with the fungus growing alone or as a member of a synthetic microbial consortium with Sphingobacterium multivorum w15 and Citrobacter freundii so4. The differential expression profiles of carbohydrate-active enzymes indicated an onset of (hemi)cellulose degradation by 2T2.1 during the initial 24 hours of incubation. Within the tripartite consortium, 63 transcripts of strain 2T2.1 were differentially expressed at this time point. The presence of the two bacteria significantly upregulated the expression of one galactose oxidase, one GH79-like enzyme, one multidrug transporter, one laccase-like protein (AA1 family) and two bilirubin oxidases, suggesting that inter-kingdom interactions (e.g. amensalism) take place within this microbial consortium. Overexpression of multicopper oxidases indicated that strain 2T2.1 may be involved in lignin depolymerization (a trait of enzymatic synergism), while S. multivorum and C. freundii have the metabolic potential to deconstruct arabinoxylan. Under the conditions applied, 2T2.1 appears to be a better degrader of wheat straw when the two bacteria are absent. This conclusion is supported by the observed suppression of its (hemi)cellulolytic arsenal and lower degradation percentages within the microbial consortium.

Isolation and characterization of novel bacterial strains for integrated solar-bioelectrokinetic of soil contaminated with heavy petroleum hydrocarbons.

This study investigated the isolation and characterization of three novel bacterial strains; Acinetobacter calcoaceticus, Sphingobacterium multivorum, and Sinorhizobium, isolated form agriculture land. From three hundred strains of bacteria, the three isolates were identified for their superior diesel degradation ability by a series of bench-scale tests. The isolates were further investigated in bench tests for their ability to grow in different diesel fuel concentrations, temperature and pH; degrade diesel fuel in vitro; and for the identification of functional genes. Semi-pilot bioelectrokinetic tests were conducted in three electrokinetic cells. An innovative electrode configuration was adopted to stabilize the soil pH and water content during the test. The genes expressed in the diesel degradation process including Lipases enzymes Lip A, LipB, Alk-b2, rubA, P450, and 1698/2041 were detected in the three isolates. The results showed that the solar panel voltage output is in agreement with the trapezoid model. The temperatures in the cells were found to be 5-7 °C higher than the ambient temperature. The electrode configuration succeeded in stabilizing the soil pH and water content, preventing the development of a pH gradient, important progress for the survival of bacteria. The diesel degradation in the soil after bioelectrokinetic tests were 20-30%, compared to 10-12% in the controls. The study succeeded in developing environmentally friendly technology employing novel bacterial strains to degrade diesel fuel and utilizing solar panels to produce renewable energy for bioelectrokinetics during the winter season.