Wroclaw University of Environmental and Life Sciences

About: Wroclaw University of Environmental and Life Sciences is a education organization based out in Wrocław, Poland. It is known for research contribution in the topics: Population & GNSS applications. The organization has 3108 authors who have published 6672 publications receiving 57774 citations.

Production of high titer of citric acid from inulin

Abstract: Citric acid is considered as the most economically feasible product of microbiological production, therefore studies on cheap and renewable raw materials for its production are highly desirable. In this study citric acid was synthesized by genetically engineered strains of Yarrowia lipolytica from widely available, renewable polysaccharide – inulin. Hydrolysis of inulin by the Y. lipolytica strains was established by expressing the inulinase gene (INU1 gene; GenBank: X57202.1) with its native secretion signal sequence was amplified from genomic DNA from Kluyveromyces marxianus CBS6432. To ensure the maximum citric acid titer, the optimal cultivation strategy–repeated-batch culture was applied. The strain Y. lipolytica AWG7 INU 8 secreted more than 200 g dm− 3 of citric acid during repeated-batch culture on inulin, with a productivity of 0.51 g dm− 3 h− 1 and a yield of 0.85 g g− 1. The citric acid titer obtained in the proposed process is the highest value reported in the literature for Yarrowia yeast. The obtained results suggest that citric acid production from inulin by engineered Y. lipolytica may be a very promising technology for industrial citric acid production.

Influence of soil properties and phosphate addition on arsenic uptake from polluted soils by velvetgrass (Holcus lanatus).

Abstract: Four kinds of soil material were used in a pot experiment with velvetgrass (Holcus lanatus). Two unpolluted soils: sand (S) and loam (L) were spiked with sodium arsenite (As II) and arsenate (As V), to obtain total arsenic (As) concentrations of 500 mg As kg(-1). Two other soils (ZS I, ZS III), containing 3320 and 5350 mg As kg(-1), were collected from Zloty Stok where gold and arsenic ores were mined and processed for several centuries. The effects of phosphate addition on plants growth and As uptake were investigated. Phosphate was applied to soils in the form of NH4H2PO4 at the rate 0.2 g P/kg. Average concentrations of arsenic in the shoots of velvetgrass grown in spiked soils S and L without P amendment were in the range 18-210 mg As kg(-1) d.wt., whereas those in plants grown on ZS I and ZS II soils were considerably lower, and varied in the range 11-52 mg As kg(-1) d.wt. The addition of phosphate caused a significant increase in plant biomass and therefore the total amounts of As taken up by plants, however, the differences in As concentrations in the shoots of velvetgrass amended and non-amended with phosphate were not statistically significant.

Efficient utilization of inulin and glycerol as fermentation substrates in erythritol and citric acid production using Yarrowia lipolytica expressing inulinase

Abstract: Inulin and glycerol were used as substrates for efficient erythritol and citric acid production by newly engineered Yarrowia lipolytica strains. Hydrolysis of inulin by the Y. lipolytica Wratislavia K1 strain was established by expressing the Kluyveromyces marxianus INU1 gene. Erythritol was produced in two stages: inulin was used for biomass formation, followed by erythritol biosynthesis initiated by glycerol addition. The highest titer of erythritol obtained, 120.9 g L−1 with the yield of 0.6 g g−1, was produced by the K1 INU 6 strain. Moreover, the K1 INU 6 strain in fed-batch culture produced a high amount of citric acid: 105.2 g L−1 after 235 h from 200 g L−1 of inulin. Maximum activity of inulinase during this culture was 14000 U g−1 of cell dry mass. The presented study proves the potential of new Y. lipolytica transformants for efficient erythritol and citric acid production from inexpensive raw materials such as inulin and glycerol.

Application of Routine Diagnostic Procedure, VITEK 2 Compact, MALDI-TOF MS, and PCR Assays in Identification Procedure of Bacterial Strain with Ambiguous Phenotype

Abstract: In diagnostic microbiology as well as in microbiological research, the identification of a microorganism is a crucial and decisive stage. A broad choice of methods is available, based on both phenotypic and molecular properties of microbes. The aim of this study was to compare the application of phenotypic and molecular tools in bacterial identification on the example of Gram-negative intestine rod with an ambiguous phenotype. Different methods of identification procedure, which based on various properties of bacteria, were applied, e.g., microscopic observation of single-bacterial cells, macroscopic observation of bacterial colonies morphology, the automated system of microorganism identification (biochemical tests), the mass spectrometry method (analysis of bacterial proteome), and genetic analysis with PCR reactions. The obtained results revealed discrepancies in the identification of the tested bacterial strain with an atypical phenotype: mucous morphology of colonies, not characteristic for either E. coli and Citrobacter spp., mass spectrometry analysis of proteome initially assigned the tested strain to Citrobacter genus (C. freundii) and biochemical profiles pointed to Escherichia coli. A decisive method in the current study was genetic analysis with PCR reactions which identified conserved genetic sequences highly specific to E. coli species in the genome of the tested strain.

Influence Carrier Agents, Drying Methods, Storage Time on Physico-Chemical Properties and Bioactive Potential of Encapsulated Sea Buckthorn Juice Powders.

Abstract: Sea buckthorn (Hippophae rhamnoides L.) juice with inulin, maltodextrin, and inulin:maltodextrin (1:2 and 2:1) were spray-, freeze- and vacuum-dried at 50, 70 and 90 °C. The study aimed to assess the impact of drying methods and carrier agents on physical properties (moisture content, water activity, true and bulk density, porosity, color parameters, browning index), chemical components (hydroxymethylfurfural and phenolic compounds) and antioxidant capacity of sea buckthorn juice powders. Storage of powders was carried out for six months. Inulin caused stronger water retention in powders than maltodextrin. Vacuum drying provided powders with the highest bulk density. Maltodextrin did not promote browning and HMF formation as strongly as inulin. More phenolic compounds were found in powders with maltodextrin. Storage increased the antioxidant capacity of powders. The results obtained will be useful in optimizing the powders production on an industrial scale, designing attractive food ingredients.