Advancing Desulfurization in the Model Biocatalyst IGTS8 via an Combinatorial Approach.

Biodesulfurization poses as an ideal replacement to the high cost hydrodesulfurization of the recalcitrant heterocyclic sulfur compounds, such as dibenzothiophene (DBT) and its derivatives. The increasingly stringent limits on fuel sulfur content intensify the need for improved desulfurization biocatalysts, without sacrificing the calorific value of the fuel. Selective sulfur removal in a wide range of biodesulfurization strains, as well as in the model biocatalyst Rhodococcus qingshengii IGTS8, occurs via the 4S metabolic pathway that involves the operon, which encodes enzymes that catalyze the generation of 2-hydroxybiphenyl and sulfite from DBT.

Interplay between Sulfur Assimilation and Biodesulfurization Activity in Rhodococcus qingshengii IGTS8: Insights into a Regulatory Role of the Reverse Transsulfuration Pathway.

Biodesulfurization is a process that selectively removes sulfur from dibenzothiophene and its derivatives. Several natural biocatalysts harboring the highly conserved desulfurization operon , which is significantly repressed by methionine, cysteine, and inorganic sulfate, have been isolated. However, the available information on the metabolic regulation of gene expression is still limited.

Magnetic Immobilization and Growth of and .

Microalgae are used in industrial and pharmaceutical applications. Their performance on biological applications may be improved by their immobilization. This study presents a way of cell immobilization using microalgae carrying magnetic properties.

Optimization of Microalga Magnetic Harvesting.

Harvesting of microalgae is a crucial step in microalgae-based mass production of different high value-added products. In the present work, magnetic harvesting of was investigated using microwave-synthesized naked magnetite (FeO) particles with an average crystallite diameter of 20 nm. Optimization of the most important parameters of the magnetic harvesting process, namely pH, mass ratio (m) of magnetite particles to biomass (), and agitation speed (rpm) of the biomass-FeO particles mixture, was performed using the response surface methodology (RSM) statistical tool.

Incorporation of Magnetic Nanoparticles into Protoplasts of Microalgae : A Tool for Biotechnological Applications.

Intensive research on the use of magnetic nanoparticles for biotechnological applications of microalgae biomass guided the development of proper treatment to successfully incorporate them into these single-cell microorganisms. Protoplasts, as cells lacking a cell wall, are extensively used in plant/microalgae genetic manipulation as well as various biotechnological applications. In this work, a detailed study on the formation of protoplasts from with the use of enzymatic and mechanical procedures was performed.

Catalytic and thermodynamic properties of an acidic α-amylase produced by the fungus ATHUM 8891.

An extracellular acid stable α-amylase from ATHUM 8891 (PV8891 α-amylase) was purified to homogeneity applying ammonium sulfate fractionation, ion exchange and gel filtration chromatography and exhibited a reduced molecular weight of 75 kDa. The purified enzyme was optimally active at pH 5.0 and 60 °C and stable in acidic pH (3.

A Study on the Effect of Macro- and Micro- Nutrients on Growth, Fatty Acid Composition and Magnetic Harvesting Efficiency.

The effect of iron, manganese, phosphorus and nitrogen on growth and lipid synthesis of the microalgae CCMP1779, as well as their impact on the magnetic harvesting efficiency, are examined under their depriving cell culture conditions. Herein, it is demonstrated that nitrogen and manganese depletion primarily reduced cell growth while phosphorus and iron restriction led to higher dry biomass. Subsequently, the role of those nutrients on fatty acids profile was examined.

Microbial Production of Violacein and Process Optimization for Dyeing Polyamide Fabrics With Acquired Antimicrobial Properties.

In the present study, crude bacterial extract containing violacein is investigated for the preparation of antimicrobial polyamide fabrics. The optimal culture conditions of (JL) for maximum biomass and violacein production were found to be 25°C, pH 7.0, while the addition of ampicillin of 0.

Studies on the catalytic behavior of a membrane-bound lipolytic enzyme from the microalgae Nannochloropsis oceanica CCMP1779.

The catalytic behavior of a membrane-bound lipolytic enzyme (MBL-Enzyme) from the microalgae Nannochloropsis oceanica CCMP1779 was investigated. The biocatalyst showed maximum activity at 50 °C and pH 7.0, and was stable at pH 7.

3-Chloro-1,2-propanediol biodegradation by Ca-alginate immobilized Pseudomonas putida DSM 437 cells applying different processes: mass transfer effects.

3-Chloro-1,2-propanediol (3-CPD) biodegradation by Ca-alginate immobilized Pseudomonas putida cells was performed in batch system, continuous stirred tank reactor (CSTR), and packed-bed reactor (PBR). Batch system exhibited higher biodegradation rates and 3-CPD uptakes compared to CSTR and PBR. The two continuous systems (CSTR and PBR) when compared at 200 mg/L 3-CPD in the inlet exhibited the same removal of 3-CPD at steady state.

Utilization of household food waste for the production of ethanol at high dry material content.

Background: Environmental issues and shortage of fossil fuels have turned the public interest to the utilization of renewable, environmentally friendly fuels, such as ethanol. In order to minimize the competition between fuels and food production, researchers are focusing their efforts to the utilization of wastes and by-products as raw materials for the production of ethanol. household food wastes are being produced in great quantities in European Union and their handling can be a challenge.

Biotechnological production of ethanol from renewable resources by Neurospora crassa: an alternative to conventional yeast fermentations?

Microbial production of ethanol might be a potential route to replace oil and chemical feedstocks. Bioethanol is by far the most common biofuel in use worldwide. Lignocellulosic biomass is the most promising renewable resource for fuel bioethanol production.

Bioconversion of dilute-acid pretreated sorghum bagasse to ethanol by Neurospora crassa.

Bioethanol production from sweet sorghum bagasse (SB), the lignocellulosic solid residue obtained after extraction of sugars from sorghum stalks, can further improve the energy yield of the crop. The aim of the present work was to evaluate a cost-efficient bioconversion of SB to ethanol at high solids loadings (16 % at pretreatment and 8 % at fermentation), low cellulase activities (1-7 FPU/g SB) and co-fermentation of hexoses and pentoses. The fungus Neurospora crassa DSM 1129 was used, which exhibits both depolymerase and co-fermentative ability, as well as mixed cultures with Saccharomyces cerevisiae 2541.

Supercritical carbon dioxide biocatalysis as a novel and green methodology for the enzymatic acylation of fibrous cellulose in one step.

Aliphatic esters of cellulose have recently raised the interest on the field of biopolymers. The objective of this work is to develop a methodology for the enzymatic acylation of cellulose with long chain fatty groups in one step. Therefore we designed a system at which fibrous cellulose was enzymatically acylated with vinyl laurate in supercritical carbon dioxide (scCO(2)) and as a result cellulose laurate was formed.

Hydrothermal processing and enzymatic hydrolysis of sorghum bagasse for fermentable carbohydrates production.

Untreated and hydrothermally treated sorghum bagasse (SB) was hydrolyzed to simple sugars by the synergistic action of cellulases and hemicellulases produced by the fungi Fusarium oxysporum and Neurospora crassa. Synergism between the two lignocellulolytic systems was maximized with the application of higher fraction of N. crassa enzymes.

Effect of pectate lyase bioscouring on physical, chemical and low-stress mechanical properties of cotton fabrics.

The main objective of the present study was to meticulously investigate an inclusive set of physicochemical and handle properties (determined through Kawabata evaluation system) of bioscoured cotton fabrics. The application of a commercial pectinase preparation, Bioprep 3000L, for a range of concentrations and treatment times, could create a pectin-free textile with low wax content. Multiple regression analysis was used to describe the effect of enzymatic process variables on pectin and waxes removal.

Cell bound and extracellular glucose oxidases from Aspergillus niger BTL: evidence for a secondary glycosylation mechanism.

Two glucose oxidase (GOX) isoforms where purified to electrophoretic homogeneity from the mycelium extract (GOXI) and the extracellular medium (GOXII) of Aspergillus niger BTL cultures. Both enzymes were found to be homodimers with nonreduced molecular masses of 148 and 159 kDa and pI values of 3.7 and 3.

Toxicity and metabolism of p-chlorophenol in the marine microalga Tetraselmis marina.

Toxicity and metabolism of para-chlorophenol (p-CP) in the marine microalga Tetraselmis marina have been studied. The inhibition constant EC(50) for p-CP was 272+/-17 microM (34.8+/-2.

Detoxification of 2,4-dichlorophenol by the marine microalga Tetraselmis marina.

Xenobiotic chlorinated phenols have been found in fresh and marine waters and are toxic to many aquatic organisms. Metabolism of 2,4-dichlorophenol (2,4-DCP) in the marine microalga Tetraselmis marina was studied. The microalga removed more than 1mM of 2,4-DCP in a 2l photobioreactor over a 6 day period.

Removal of 1,3-dichloro2-propanol and 3-chloro1,2-propanediol by the whole cell system of pseudomonas putida DSM 437.

The removal of 1,3-dichloro-2-propanol (1,3-DCP), 3-chloro-1,2-propanediol (3-CPD) and their mixtures at concentrations up to 1,000 mg . L(-1) by the whole cell system of Pseudomonas putida DSM 437 was investigated. The 1,3-DCP removal rates ranged from 2.

Biodegradation of phenol by acclimatized Pseudomonas putida cells using glucose as an added growth substrate.

Biodegradation of phenol, a pollutant derived from many industrial processes, was achieved through acclimatized Pseudomonas putida cells. The strategy to overcome the inhibitory effect of phenol on microbial growth involved the addition of glucose, a conventional carbon source. A factorial experimental design was employed in order to optimize the initial phenol and glucose concentrations.

Combined photo-assisted and biological treatment of industrial oily wastewater.

In the present study an oily wastewater from the lubricant unit of a petroleum company was evaluated by combining the sequence photo-assisted oxidation-Pseudomonas putida DSM 437. The wastewater contained various alcohols, acids and phenolic compounds. From the above mentioned compounds the biodegradation of ethylene glycol, phenol, o-cresol and p-cresol was examined.

Induction, purification, and characterization of two extracellular alpha-L-arabinofuranosidases from Fusarium oxysporum.

In the presence of L-arabinose as sole carbon source, Fusarium oxysporum produces two alpha-L-arabinofuranosidases (ABFs) named ABF1 and ABF2, with molecular masses of 200 and 180 kDa, respectively. The two F. oxysporum proteins have been purified to homogeneity.