Changes in soil properties and possibilities of reducing environmental risks due to the application of biological activators in conditions of very heavy soils

This study aims at verifying the effect of farmyard manure (FYM) and of selected activators (Z'fix and NeoSol) on changes of soil properties. Their application should lead to improvement of soil physical properties and of organic matter fixation, to reduction of environmental risks, e.g. of tillage energy requirements. Experimental variants (0.7 ha each) were as follows: I (FYM with Z'fix); II (FYM with Z'fix + NeoSol); III (FYM); IV (Control NPK only). FYM was applied at rates: 50 t ha-1 (2014); 30 t ha-1 (2016). Additional NPK fertilizer (I–IV) was applied according to annual crop nutrient normative. The agent Z'fix was used as an activator of FYM biological transformation (5.5 kg t -1 ). The agent NeoSol was used as soil activator (200 kg ha-1 ; annually). In order to verify the effect, cone index, bulk density, tillage implement draft and chemical soil components (Humus, C/N ration and Ntot) were measured annually. Compared to the control, the application of FYM combined with the mentioned agents (I–III) increased Ntot more than two times. Moreover, it decreased (I–III) bulk density by 8.7%. Tillage implement draft decreased by 3% after the application of FYM with Z’fix (I, II). The study confirmed that FYM application combined with utilization of activators positively influenced soil fertility and helped to reduce environmental risks

E1 Enzyme of the Pyruvate Dehydrogenase Complex in Corynebacterium glutamicum: Molecular Analysis of the Gene and Phylogenetic Aspects

The E1p enzyme is an essential part of the pyruvate dehydrogenase complex (PDHC) and catalyzes the oxidative decarboxylation of pyruvate with concomitant acetylation of the E2p enzyme within the complex. We analyzed the Corynebacterium glutamicum aceE gene, encoding the E1p enzyme, and constructed and characterized an E1p-deficient mutant. Sequence analysis of the C. glutamicum aceE gene and adjacent regions revealed that aceE is not flanked by genes encoding other enzymes of the PDHC. Transcriptional analysis revealed that aceE from C. glutamicum is monocistronic and that its transcription is initiated 121 nucleotides upstream of the translational start site. Inactivation of the chromosomal aceE gene led to the inability to grow on glucose and to the absence of PDHC and E1p activities, indicating that only a single E1p enzyme is present in C. glutamicum and that the PDHC is essential for the growth of this organism on carbohydrate substrates. Surprisingly, the E1p enzyme of C. glutamicum showed up to 51% identity to homodimeric E1p proteins from gram-negative bacteria but no similarity to E1 α- or β-subunits of heterotetrameric E1p enzymes which are generally assumed to be typical for gram-positives. To investigate the distribution of E1p enzymes in bacteria, we compiled and analyzed the phylogeny of 46 homodimeric E1p proteins and of 58 α-subunits of heterotetrameric E1p proteins deposited in public databases. The results revealed that the distribution of homodimeric and heterotetrameric E1p subunits in bacteria is not in accordance with the rRNA-based phylogeny of bacteria and is more heterogeneous than previously assumed

l-Valine Production with Pyruvate Dehydrogenase Complex-Deficient Corynebacterium glutamicum

Corynebacterium glutamicum was engineered for the production of l-valine from glucose by deletion of the aceE gene encoding the E1p enzyme of the pyruvate dehydrogenase complex and additional overexpression of the ilvBNCE genes encoding the l-valine biosynthetic enzymes acetohydroxyacid synthase, isomeroreductase, and transaminase B. In the absence of cellular growth, C. glutamicum ΔaceE showed a relatively high intracellular concentration of pyruvate (25.9 mM) and produced significant amounts of pyruvate, l-alanine, and l-valine from glucose as the sole carbon source. Lactate or acetate was not formed. Plasmid-bound overexpression of ilvBNCE in C. glutamicum ΔaceE resulted in an approximately 10-fold-lower intracellular pyruvate concentration (2.3 mM) and a shift of the extracellular product pattern from pyruvate and l-alanine towards l-valine. In fed-batch fermentations at high cell densities and an excess of glucose, C. glutamicum ΔaceE(pJC4ilvBNCE) produced up to 210 mM l-valine with a volumetric productivity of 10.0 mM h(−1) (1.17 g l(−1) h(−1)) and a maximum yield of about 0.6 mol per mol (0.4 g per g) of glucose