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New Window Opens on the Secret Life of Microbes: Scientists Develop First Microbial Profiles of Ecosystems
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Applied Biochemistry and Microbiology (v.47, #9)
Microalgae as source of biofuel, food, fodder, and medicines by S. D. Varfolomeev; L. A. Wasserman (pp. 789-807).
Current status and future prospects of such problem as the production of microalgae and their application for biofuel generation (biodiesel, biohydrogen, bioethanol), as well as other products, is discussed in the review. The use of microalgae in human food, fodder, cosmetics, dyes, polysaccharides, antioxidants, medicines, and other products is quite promising. Presently, microalgae are noncompetitive with plant materials, due to economic reasons, in serving as a source of biofuel. Thereby, it is urgently necessary in modern biotechnology to improve the methods for the production of microalgae and search for new ways of their processing.
Effect of submerged cultivation conditions and inducers on biosynthesis of extracellular laccase by a Trametes versicolor 1666 strain by N. V. Shakhova; S. A. Golenkina; E. V. Stepanova; D. S. Loginov; N. V. Psurtseva; T. V. Fedorova; O. V. Koroleva (pp. 808-816).
Genetic analysis of basidiomycete Trametes versicolor 1666 from the Komarov Botanical Institute (LEBIN) Collection has been carried out that verified the phylogenetic position of the strain and revealed the presence of a single laccase gene. A study of cultivation dynamics of basidiomycete showed a low level of laccase, peroxidase, and Mn-peroxidase production on glucose-peptone and mineral media. The level of laccase activity in the culture liquid (CL) remained practically unchanged during cultivation in a medium optimized using full factorial experiment as compared to the standard medium. An addition of laccase inducers (syringaldazine, caffeic acid, and synaptic acid) had no effect on the enzyme activity in the culture liquid. Real time PCR showed a lack of reliable difference in the level of laccase gene expression when cultivating the strain under optimal conditions with and without copper ions in the medium. The transcription behavior of laccase gene and occurrence of enzyme activity when cultivating T. versicolor 1666 strain testify to the enzyme constitutive synthesis and the existence of additional regulatory ways in the laccase gene expression.
Keywords: basidiomycete; gene; identification; enzyme induction; laccase; peroxidase; full factorial experiment; transcripts of laccase mRNA
Isolation, identification, and antifungal activity of a Gamair complex formed by Bacillus subtilis M-22, a producer of a biopreparation for plant protection from mycoses and bacterioses by I. I. Novikova; Yu. D. Shenin (pp. 817-826).
A metabolic complex, Gamair, has been isolated from Bacillus subtilis strain M-22, a producer of a biopreparation for plant protection from diseases of various etiologies. Gamair was shown to possess a broad spectrum of activity against phytopathogenic bacteria (including Pseudomonas corrugata, Erwinia carotovora, Clavibacter michiganensis subsp. michiganensis, and Xantomonas campestris pv. vesicatoria), and fungi (Fusarium, Verticullum, Ascochyta, Colletotrichum, Rhizoctonia, Sclerotinia, Septoria, and other genera). Using NMR and IR spectroscopy, it was shown that the complex of active compounds is a mixture of the following fractions: Gamair A (close to bacillin), and Gamair B-D (mediocin type hexaene-like) antibiotics. The chemical and biological properties of the above fractions were investigated. In field trials using tomato plants, it was demonstrated that the biological efficacy of Gamair against bacterial wilt, stem core necrosis, and vegetable's mild rot reached 70–90%, whereas the harvest increase was 25-35%.
Keywords: antibacterial activity; isolation; hexaene-like antibiotics; identification; polypeptide antibiotics; fermentation; phytopathogenic fungi and bacteria; fungicidal activity; chromatography
Study of structural and rheological properties of starch isolated from genetically modified potato by A. V. Kanarskii; Z. A. Kanarskaya; D. Sh. Yagofarov; L. A. Wasserman; V. G. Vasil’ev; K. G. Skryabin; A. M. Kamionskaya (pp. 827-832).
It has been found in this work that the starchiness and starch content in tubers of GM potato and tubers of initial Lugovskoi potato variety are identical. No differences and difficulties were observed upon starch preparation from GM and common potato. Starch samples isolated from GM potato conform to the current standard for potato starch. The starch isolated from GM potato has a higher melting point, i.e., it is more thermally stable as compared with the starch isolated from a control sample. The bulk modulus of gels obtained from starch isolated from GM potato is higher in comparison with that of gels prepared from starch isolated from the control sample. Thermodynamic and rheological properties of starch from GM potato provide a possibility to predict its application in the manufacture of thermostable and strong polymeric materials.
Keywords: genetically modified potato; starch; rheological properties; melting point; processing properties
Two-stage process of bacterial-chemical oxidation of refractory pyrite-arsenopyrite gold-bearing concentrate by P. A. Zaulochnyi; A. G. Bulaev; E. E. Savari; T. A. Pivovarova; T. F. Kondratieva; G. V. Sedelnikova (pp. 833-840).
A technology for tank biooxidation of refractory gold-bearing concentrate under variable temperature conditions has been improved: the temperature of the first of two stages was changed from 30°C to 34–36°C. Gold in this concentrate is mainly associated with sulfide minerals: arsenopyrite and pyrite, which underlies a low gold recovery (16.68%) as a result of cyanidation. To resolve the problem, an association of mesophilic acidophilic chemolithotrophic microorganisms and moderately thermophilic bacteria of the Sulfobacillus genus were used for the concentrate oxidation. The composition of the used microbial association was studied; it was shown that it depends upon temperature: at 42°C, the population of the mesophilic thiobacteria decreased, whereas that of thermophilic sulfobacilli enhanced as compared to 36°C. The accepted scheme of the process ensures a high extent of gold recovery (94.6%) within a short space of time for biooxidation (96 h).
Keywords: arsenopyrite; bioleaching; chemolithotrophic acidophilic microorganisms; moderately thermophilic microorganisms; pyrite; refractory gold-bearing concentrate
Optimizations of sulphide and organic modifications of the DEAMOX process by A. I. Trukhina; M. A. Gladchenko; S. V. Kalyuzhnyi (pp. 841-845).
Effect of various operational parameters (pH, bicarbonate concentration, and temperature) on the efficiency of the S- and O-modifications of the DEAMOX process was studied. It was demonstrated that the optimum pH values for the S- and O-DEAMOX processes are 7.5 ± 0.05 and 8.1 ± 0.08, respectively. The optimum bicarbonate concentration for both modifications does not exceed 24 mM. The optimum temperature for the S-DEAMOX process is 35°C, and any deviation from this value has a significant impact on this process. For the O-DEAMOX process, the optimum temperature range is 25–35°C.
Keywords: anaerobic processes; anammox; bicarbonate; temperature; DEAMOX; pH
Biosensor monitoring of microbial treatment of wastewater from nonylphenol polyethoxylates under flow-through conditions by Yu. V. Plekhanova; A. N. Reshetilov; T. V. Manolov; L. A. Taranova (pp. 846-851).
Biodegradation of nonylphenol polyethoxylates (NPEO) has been studied in laboratory column bioreactors with a polyethylene carrier on which destructor bacteria of Pseudomonas surface-active compounds were immobilized. To monitor the efficiency of microbial treatment of model wastewater, a biosensor based on the oxygen Clark electrode and destructor bacteria of NPEO from bioreactors was designed. The designed biosensor allowed us to detect the content of polyethylene glycol monoalkyl phenyl ether on the basis of polymer distillate (OP-10), which is a commercial NPEO preparation, in samples in the range of 1–200 mg/l. Operation of the biosensor was stable within 7 days with the standard deviation of 1.35 mg/l for 20 consecutive measurements of OP-10 concentration, which was 20 mg/l (7%).