卷 55, 编号 4 (2019)

The data on the effect of oil and oil products on soil, soil microbiocenosis, and plant cover are summarized. Reclamation and its stages and the bioremediation of oil-contaminated soils with the use of biological products are described. The article discusses some techniques to accelerate hydrocarbon biodegradation in the soil environment, such as the use of biosurfactants and their microorganisms; the introduction of polyfunctional bacteria that are capable of pollutant destruction and diazotrophy; the introduction of psychrotolerant microorganisms under cold climate conditions; and the use of microbial-plant complexes.

Enzymatic synthesis of pinoresinol-α-glucosides (PG_s) was performed through the transglycosylation reaction catalyzed by the recombinant cyclodextrin glycosyltransferase (CGTase) from Bacillus circulans A11 using β-cyclodextrin as the glycosyl donor and pinoresinol as the acceptor molecule. Incubation of 0.5% (wt/vol) β-cyclodextrin with 1.5% (wt/vol) pinoresinol (P) and 80.0 U/mL of CGTase in 20 mM of Tris–HCl buffer (pH 9.0) at 50^oC for 60 h was optimal for PG_s synthesis. Under these conditions, two PG transfer products with molecular weights of 544 and 682 Da corresponding to pinoresinol monoglucoside (PG₁-I and PG₁-II) and pinoresinol diglucoside (PG₂), respectively, were detected by TLC and MS. The structures of PG₁ and PG₂ were confirmed as pinoresinol-α-D-glucopyranoside and pinoresinol-α-D-diglucopyranoside, respectively, by ¹H-NMR analysis. The free-radical scavenging and anti-inflammatory activities of PG₁ and PG₂ were reduced as compared with the original P using α,α-diphenyl-β-picrylhydrazyl radical scavenging reactions and the β-glucuronidase inhibition assay. The loss of antioxidant and anti-inflammatory activities might result from the addition of glucose in the position 4-OH of P that may have disturbed its electron rotation. In vivo, PG_s are converted to P_s before they are absorbed and so loss of activity may be minimal. Interestingly, the α-glycosylated compounds which showed the change of physicochemical properties such as increase of solubility and sweetness could promote a positive effect on the bioavailability of original P.

To develop the technology for CO₂ sequestration, the free and immobilized carbonic anhydrase treatment was performed. The amount of dissolved CO₂ was increased by 3-fold after enzyme treatment of 5 ppm, and the amount of calcium carbonate increased linearly as the CaCl₂ was increased to 100 mM. To immobilize the carbonic anhydrase, an aluminum oxide carrier surface was functionalized with octadecyltrichlorosilane, 1H,1H,2H,2H-perfluoroctyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyl triethoxysilane, chlorotrimethylsilane 3-cyanopropyltrichlorosilane or 3-glycidyloxypropyltriethoxysilane. The best effect among these substances was revealed with 3-aminopropyltriethoxysilane; the efficacy of the immobilized carbonic anhydrase was at over 99%, and even when it was repeatedly used up to 40 times, the efficacy of the immobilized enzyme was more than 80%. The optimal conditions for the immobilized enzyme were 60^oC and pH 7.0.

Whole-genome sequencing of bacteria Bacillus velezensis BIM B-439D has revealed that its genome is represented by a single circular chromosome 3 978 954 bp in size and contains 3969 predicted genes. Chromosome has 10 conserved loci that determine the production of antimicrobial compounds of varying chemical nature, namely lipopeptides (surfactin, bacillomycin, fengycin), polyketides (bacillaene, difficidin/oxydifficidin, macrolactin), bacillibactin siderophore, dipeptide bacilysin, a protein/polyketide of uncertain composition, and amylocyclicin bacteriocin. Mutants with impaired surfactin synthesis have been obtained by direct mutagenesis; they were characterized by an increased production of bacillomycin and fengycin. The obtained mutants demonstrated high antimicrobial activity towards a number of bacterial and fungal pathogens (Penicillium expansum, Alternaria tenuis, Botrytis cinerea,Bipolaris sorokiniana), but they inhibited the growth of the Fusarium genus fungi to a lesser degree.

The effect of the main characteristics of low molecular weight chitosan obtained via enzymatic and chemical hydrolysis with a molecular mass (MM) of 2–100 kDa, a deacetylation degree (DD) of 60–98%, and a polydispersity (Mw/Mn) of 1.9–2.7 on the growth of Botrytis cinerea has been studied. The greatest inhibitory effect on the fungal germination process (a conidia germination index of less than 50%) was provided by chitosan samples with an MM of 2–13 kDa, a DD of 85–98%, and a polydispersity of 2–2.5. Among the most effective was chitosan with an MM of 13 kDa and a deacetylation degree 98%, which had a significant inhibitory effect on the growth of the fungal mycelium at concentration 0.938 mg/mL. This sample of chitosan and its complex with copper ions (75 ppm) significantly suppressed fungal metabolic activity (up to 20 and 10%, respectively), which indicates their high potential as antifungal agents for the development of fungicides.

Acinetobacter calcoaceticus has been reported to be a good candidate for removing various pollutants. In this study, A. calcoaceticus T32 could remove 100% \({\text{NH}}_{4}^{ + }\)-N and 98% of total inorganic nitrogen within 48 h, with production of traces of \({\text{NO}}_{2}^{ - }\) and \({\text{NO}}_{3}^{ - }\). The gene of subunit of ammonia monooxygenase (AMO), amoA_Ac, was cloned from A. calcoaceticus. Real-time reverse transcriptase PCR showed that mRNA level of amoA_Ac was 22-fold higher when \({\text{NH}}_{4}^{ + }\) was present, and retained to normal level in the presence of 50 mg/L allylthiourea, an inhibitor of AMO. mer operon containing merT, merP and merA genes involved in mercury resistance was fused into plasmid JR20 and introduced into A. calcoaceticus T32 through bacterial conjugation, constructing A. calcoaceticus T32/JRHg, which removed 93% HgCl₂. LD₅₀ of A. calcoaceticus T32 was 6.19 × 10⁸ CFU using model with Japanese flounder, suggesting that A. calcoaceticus T32 might be environmentally friendly to treat nitrogen and mercury pollutants.

A method is proposed for reducing the detection limit of enzyme-linked immunosorbent assay (ELISA) of potato virus X, based on the multiple introduction of tyramine into immune complexes and the subsequent detection of an enzyme label. During ELISA, a step by step formation of sandwich complex containing immobilized antibodies – potato virus X – horseradish peroxidase conjugate with antibodies to the virus was carried out. Peroxidase catalyzed the multiple insertion of a tyramine-biotin label into protein molecules, providing signal amplification upon the addition of the streptavidin-polyperoxidase conjugate. The conditions of the assay that ensure a high degree of amplification and a minimum background signal were established. The use of tyramine amplification made it possible to lower the detection limit by more than 30 times (from 100 to 3 ng/ml) when assayed in the buffer and extracts of potato leaves, slightly increasing its duration. Tyramine amplification is based on the use of universal reagents and can be used to reduce the detection limit of ELISA for other antigens.