ABSTRACT
In this study, a novel harvesting emulsion (HEM) consisting of cooking oil in an aqueous solution of cetyltrimethylammonium bromide (CTAB) was tested for the harvesting of a technologically important microalga, Chlorella vulgaris. The influence of HEM dose, biomass and bovine serum albumin (BSA) (model interferer compound) on harvesting efficiency (E) were studied. The HEM E was over 90% at pH 10 (0.33% (v/v) cooking oil, 6.7 mg/L of CTAB) and 12 (0.13% (v/v) cooking oil, 2.7 mg/L of CTAB). Harvesting efficiencies at pH 4 and 7 were < 73.5% due to the absence of precipitate formation. Bovine serum albumin (10 mg/L) increased the HEM dose necessary to achieve E Ë 90% by 1.2 (pH 10), and 3 fold (pH 12). By manipulating the dose of HEM and pH, the method of harvesting (flocculation/sedimentation or flotation) was adjustable depending on the technological requirements.
Subject(s)
Chlorella vulgaris , Microalgae , Biomass , Cooking , Flocculation , Surface-Active Agents , WaterABSTRACT
Three bottles of different beers were found in 2015 during a reconstruction of the brewery of the Raven Trading s.r.o. company in Záhlinice, Czech Republic. Thanks to good storage conditions, it was possible to analyze their original characteristics. All three bottles contained most probably lager type beer. One beer had sulfuric and fecal off-flavors; it was bright with the original extract of 10.3° Plato. The second beer, with an original extract of 7.6° Plato, was dark and very acidic, resembling Lambic. DNA analysis proved the presence of Dekkera bruxellensis, which corresponded to its chemical profile (total acidity, FAN, ethyl acetate, total esters). The third beer contained traces of carbon dioxide bubbles, was light brown and slightly bitter, with an original extract 10.4° Plato. Because it obviously underwent a natural aging process, sweetness, honey, and fruity off-flavors were detected and transformation products of iso-α-acids were found.
Subject(s)
Beer/analysis , Acids/analysis , Beer/microbiology , Czech Republic , Dekkera/genetics , Dekkera/isolation & purification , Dekkera/metabolism , Fatty Acids/analysis , Fermentation , Flavoring Agents/analysis , Food Handling , Humans , Time FactorsABSTRACT
PCR-primers were designed for identification of strictly anaerobic bacteria of the genus Zymophilus based on genus-specific sequences of the 16S-23S rDNA internal transcribed spacer region. The specificity of the primers was tested against 37 brewery-related non-target microorganisms that could potentially occur in the same brewery specimens. None DNA was amplified from any of the non-Zymophilus strains tested including genera from the same family (Pectinatus, Megasphaera, Selenomonas), showing thus 100% specificity. PCR assay developed in this study allows an extension of the spectra of detected beer spoilage microorganisms in brewery laboratories.
Subject(s)
Bacteria, Anaerobic/classification , Bacteria, Anaerobic/genetics , DNA, Intergenic/genetics , RNA, Ribosomal/genetics , Anaerobiosis , Bacteria, Anaerobic/metabolism , Base Sequence , DNA, Intergenic/chemistry , Molecular Sequence Data , Polymerase Chain Reaction , RNA, Ribosomal/chemistry , Sensitivity and Specificity , Sequence AlignmentABSTRACT
The methods of preparation of fatty acids from brewer's yeast and its use in production of biofuels and in different branches of industry are described. Isolation of fatty acids from cell lipids includes cell disintegration (e.g., with liquid nitrogen, KOH, NaOH, petroleum ether, nitrogenous basic compounds, etc.) and subsequent processing of extracted lipids, including analysis of fatty acid and computing of biodiesel properties such as viscosity, density, cloud point, and cetane number. Methyl esters obtained from brewer's waste yeast are well suited for the production of biodiesel. All 49 samples (7 breweries and 7 methods) meet the requirements for biodiesel quality in both the composition of fatty acids and the properties of the biofuel required by the US and EU standards.
Subject(s)
Biofuels/analysis , Industrial Microbiology/methods , Saccharomyces cerevisiae/metabolism , Fatty Acids/chemistry , Fatty Acids/metabolism , Fermentation , Lipids/chemistry , Nitrogen/metabolism , Saccharomyces cerevisiae/chemistryABSTRACT
High resolution electrospray ionization tandem mass spectrometry (HR-ESI-MS/MS) was used to analyze cardiolipins (Ptd2Gro) including their plasmalogen forms from three species of the anaerobic beer-spoilage bacterial genus Pectinatus. Cardiolipins including their plasmalogens were analyzed by HR-ESI-MS/MS on Orbitrap and almost 100 cardiolipins (i.e. tetra-acyl--Ptd2Gro, plasmenyl-tri-acyl--PlsPtd2Gro, and di-plasmenyl-di-acyl--Pls2Ptd2Gro) of three classes were identified. The structures of the molecular species that consist of various regioisomers and structurally similar compounds were revealed in detail. The high resolution mass spectrometry allowed the unambiguous structural assignment of Ptd2Gro, PlsPtd2Gro, and Pls2Ptd2Gro in the three species of Pectinatus, which contain predominantly odd numbered fatty acids.
Subject(s)
Cardiolipins/chemistry , Pectinatus/chemistry , Plasmalogens/chemistry , Spectrometry, Mass, Electrospray Ionization/methods , Tandem Mass Spectrometry/methods , Beer/microbiology , Cardiolipins/analysis , Food Contamination , Food Microbiology , Molecular Structure , Plasmalogens/analysisABSTRACT
Liquid chromatography-electrospray tandem mass spectrometry (LC/ESI-MS/MS) was used to analyze phospholipids from three species of the anaerobic beer-spoilage bacterial genus Pectinatus. Analysis of total lipids by HILIC (Hydrophilic Interaction Liquid Chromatography) column succeeded in separating diacyl- and plasmalogen phospholipids. Plasmalogens were then analyzed by means of the ESI-MS/MS and more than 220 molecular species of four classes of plasmalogens (PlsCho (choline plasmalogen), PlsEtn (ethanolamine plasmalogen), PlsGro (glycerol plasmalogen), and PlsSer (serine plasmalogen)) were identified. Major molecular species were c-p19:0/15:0 PlsEtn and PlsSer, which accounted for more than 4% of the total lipids.
