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Recently, due to global concerns regarding the growing accumulation of waste, increased attention is directed towards new ways of using lignolytic enzymes, as a means of reducing environmental pollution coupled with obtaining new useful products. Valorization of lignocellulosic food waste and its components into different value-added products requires disruption of the recalcitrant structure of the lignocellulosic component. In this paper lignolytic enzymes produced by phyllum Basidiomycota, as well as other enzymes that participate in the degradation of agri-food waste are summarized. The aim of this review is to give an overview on the biosynthesis and use of laccases for enzymatic treatment applied to agri-food waste. The methodology consisted in the research of the most representative sources from the literature of recent years and the synthesis of the respective studies, for an overall study. There are presented different types of agri-food waste generated by the fruit and vegetable, grain, wine, and beer processing industries. The main species of basidiomycetes that produce lignocellulosic enzymes are mentioned, as well as the conditions for their cultivation. The methods of selecting the producing fungal strains by screening on chromogenic media, the analysis of the enzyme activity, the stages of the biosynthesis process, the factors that influence the accumulation of the enzyme are described. The article includes information related to the structure and treatment of lignocellulosic materials from vegetable food waste, the mechanism of action of laccase, as well as the current state of research in the direction of using these enzymes for the treatment of food waste. [ABSTRACT FROM AUTHOR]

Currently, due to global concerns regarding energy security and its environmental consequences, biomass has been promoted as an important resource for reducing greenhouse gas emissions through its conversion into biofuels. The main limitation in the use of lignocellulosic substrate for biofuel production is its resistant structure. Pretreatment is a necessary step to overcome the lignocellulosic biomass rigid structure and to improve its biodegradability for energetic conversion (biomethane, biohydrogen, bioethanol, etc.). Lately, a number of pretreatment methods have been studied and applied, such as physical, thermal, chemical and biological pretreatment which can be used individually or in combination. Compared to physical and chemical pretreatment techniques, biological pretreatment usually requires much lower energy consumption and does not involve the use of chemicals, which presents economic advantages and a minimal impact on the environment. The anaerobic digestion process has proven to be an effective technology for converting organic substrate into energy in the form of biogas. Including a pretreatment technique in anaerobic digestion processes increases lignocellulosic biomass digestibility and improves the biogas yield. The aim of this review is to give an overview on the enzymatic pretreatment applied to lignocellulosic biomass substrate used for biogas production. There are presented different types of enzymes, namely cellulase, lipase, amylase, protease, and ligninolytic enzymes which are responsible for the degradation of lignocellulosic substrate. The article includes information related to the structure of lignocellulosic biomass, the advantages of biological pretreatment, as well as the current state of research in the direction of enzymatic treatment to enhance the anaerobic digestion process. [ABSTRACT FROM AUTHOR]

An UV absorption spectroscopy technique for real time detecting of reactive ozone and nitrogen oxides species in ozonated water was compared with the traditional iodometric method. The UV absorption spectra are important for understanding the composition of ozonated water. A commercially available ozone generator was used to obtain ozonated water by the bubbling method. A volume of 200 ml of distilled water was treated with the gaseous mixture resulted from the ozone generator. The UV absorption spectra were recorded between 200-300 nm and the ozone concentration wasdetermined by the iodometric method. The results showed the presence of some characteristic peaks for nitrogen oxides and ozonespecies in the UV absorption spectra, the values of the absorbance increasing in time. It has been shown that, due to the high nitrogen content in the air passed through the corona discharge, nitrogen oxides are mainly produced and less ozone. This could explain also the strong decrease of the pH values, after one hour of water ozonation. The iodometric analysis method showed the synthesis of some agents with strong oxidative potential, which can be both ozone and nitrogen oxides. The water sample treated for one hour with the ozone generator was analysed again after one week and one month, the results showing that reactive oxidizing species were kept also after this time. The UV absorption spectra, concentration of ozone (g·l-1) determined by the traditional iodometric method and evolution of the pH values were assessed. [ABSTRACT FROM AUTHOR]

Because of its excellent disinfection and oxidation qualities, ozone is widely used for drinking water treatment. Ozone is frequently used to destroy and inhibit the growth of microorganisms from contaminated water. In this paper, ozone efficiency was tested for water treatment containing cell suspensions of Escherichia coli K12-MG 1655, Enterococcus faecalis ATCC 29212 and Pseudomonas aeruginosa ATCC 9027 using an ozone generator OZONFIX 8G. Water samples were subjected to ozone treatment for different periods, ranging from 15 seconds to 15 minutes. Ozone was generated by the corona discharge method. The use of electrical power to generate ozone by corona discharge is the most commercially viable method. Analyses were performed both for determining the cell viability by the total plate count technique, and for determination of the cell growth curves after the applied ozone treatment. The bacteria were cultured in liquid media on an orbital shaker at 150 rpm and 37° C. The bacterial multiplication was measured by recording the absorbance A600nm on a UV-VIS spectrophotometer. Following the experiments, it was found that ozone showed a strong effect of inhibiting the growth of the three bacterial strains, both in terms of viability and multiplication capacity. The most resistant was the bacterial strain of Pseudomonas aeruginosa ATCC 9027. [ABSTRACT FROM AUTHOR]

Escherichia coli K12-MG1655 was cultivated in minimal media containing different concentrations of glucose, at 27 °C, on an orbital incubator, at 150 rpm. The growth curves demonstrated that the OD at 600 nm correlated to the cell density depends on the concentration of the carbon source, being higher for 1% and 0.5% glucose. The exponential phase stops after 10-12 hours for the lowest concentrations of glucose (0.02% and 0.05%) and continues for up to 16-17 hours for the highest concentrations, that can be explained by the nutrient limitation. The results of glucose consumption showed a slow decrease in glucose concentration for the first 4-5 hours corresponding to lag phase of growth. In the next 10 hours, the glucose consumption is high, and after 14 hours the concentration of this nutrient decreases to 1.5% after 11 hours for the initial concentration of 0.05%, and to 6% after 14 hours for 0.1% initial concentration of glucose. [ABSTRACT FROM AUTHOR]

The essential oils have a potential interest in the pharmacological field and in food preservation technology for its antimicrobial effects and receive particular attention as agents suitable for prophylactic and medical treatment. The aim of this paper was to demonstrate the in vitro the static and/or cidal activity of essential oils extracted from six aromatic plants found in the local flora: thyme, mint, basil, dill, sage, oregano. These oils were tested against four bacterial strains: E. coli ATCC 8738, Salmonella enteritidis ATCC 13076, Staphilococcus aureus ATCC 6538, and Pseudomonas aeruginosa ATCC 9027 through agar well diffusion method. All microbial strains were completely or partially inhibited by the volatile oils. The most effective antibacterial were oregano and thyme oils that inhibit the growth of E. coli and S. aureus. The lowest effect was recorded in the case of sage and basil oils for all tested germs. P. aeruginosa was the most resistant bacterial species. [ABSTRACT FROM AUTHOR]

Carotenoids pigments are of great interest to many areas because of their wide distribution in nature and their benefits for health. Rhodotorula rubra produces carotenoid pigments when growing in submerged cultures containing sugars, nitrogen sources, growth factors and salts. Among the carotenoid pigments, this yeast synthesizes small quantities of torularhodin, the only pigment with antioxidant properties. The influence of carbon and nitrogen sources on composition of carotenoid mixture in culture media is significant. The Rhodotorula rubra strain was grown in shaken, submerged cultures on appropiate medium with different nitrogen sources: NaNO3, Ca(NO3)2, (NH4)2C6H6O7, (NH4)2SO4, NH4Cl. The daily values of absorbance, pH, total soluble solids in culture media were recorded and the carotenoid pigments were extracted in acetone, n-hexane and alkaline methanol. [ABSTRACT FROM AUTHOR]

Biogas production obtained from agricultural and animal residues, municipal solid wastes, specific energy crops and sludge from wastewater in anaerobic digesters, has been studied experimentally and theoretically worldwide. The anaerobic digestion is the most used technology for treatment and energy recovery from different kinds of organic residues. In the present paper, the influence of substrate parameter on the performance of anaerobic digestion process was studied in order to determine the optimal biogas production. The substrate used in anaerobic digestion process was made of miscanthus biomass and poultry manure in different proportions. The results obtained from the experiments on the co-digestion of these two substrates showed that the addition of 10,5% poultry manure improved the biogas production. [ABSTRACT FROM AUTHOR]

Essential oil plants and culinary herbs include a broad range of plant species that are used for their aromatic value in aromatherapy, as flavorings in foods and beverages and as fragrances in pharmaceutical and industrial products. Essential oils derive from aromatic plants of many genera distributed worldwide. Essentials oils obtained from plant material have been used for centuries as antimicrobial agents. The increase of microbial resistance to antibiotics and the efforts to develop natural preservatives in food manufacturing has increased interest in possible applications of these compounds. The aim of this study was to determine antimicrobial activity of essentials oils against some fungal foodborne and agricultural strains belonging Aspergillus, Penicillium and Fusarium genera. The antifungal effect of volatile phase of essential oils was evaluated in vitro by measuring the diameter of the mold colony growth in Petri dishes, on potato dextrose agar. Mycelial growth assay showed fungistatic and fungicidal activity of cinnamon, mint, basil and thyme. Orange and lemon oils show a weak inhibitory activity on these fungi. On microscopic slides were observed alterations of normal appearance of conidiospores and hyphal system. Spores production was inhibited by the essential oils tested and the hyphae are thinner than normal, with large vacuoles. [ABSTRACT FROM AUTHOR]

The organic pollutants of soil like associated petroleum hydrocarbons are a major source of concern for food safety, especially in underdeveloped and developing countries of the world. The increasing concentrations of toxic compounds in agricultural soils contaminated with organic pollutants affect physiology, biochemistry and development and growth of crops, and overall productivity. Organic pollutants can degrade soil structure, disrupt microbial communities, and reduce soil fertility. Due to the difference in the composition and concentration of the different organic pollutants, they have impact on soil, on plant growth and development in different ways and at different rates. The current review aims to give an overview of the response of plants to organic pollution according to factors such as the type, composition, concentration, persistence of organic pollutants, type and characteristics of soil, plant species and climate. Petroleum hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) are part of the most significant classes of organic pollutants, due to their long-term environmental persistence, long-term toxicity, bioaccumulation, and biomagnification properties of living tissues. Up to 90% of all petroleum hydrocarbons are deposited in the soil due to their high hydrophobicity, which improves the rapid interaction with soil particles and their permeability in the lower layers. Thus, this review summarizes the current state of research on the effects of organic pollutants, hydrocarbons especially, on physiology, biochemistry, development and growth of crops. [ABSTRACT FROM AUTHOR]

Obtaining bioethanol from lignocellulosic substrates is conditioned by degradation of vegetal substrates as much as possible. A fungal strain of Sporotrichumpulverulentumwas characterized morphologically and from enzyme production point of view in order to degrade corn stalks and wheat straw to obtain fermentable sugars. The production of hydrolytic enzymes (cellulases, amylases, proteases, lipases) was tested by qualitative analysis methods on specific culture media. The production of laccase, the enzyme involved in lignin degradation, was evaluated using guaiacol as substrate. The Sporotrichumpulverulentum strain was cultured on a rotary incubator at 150 rpm and 30 °C for 3 days to obtain the biomass used for inoculating the bioreactor. Substrate was physicochemically analysed for total solids (TS) and a dimensional analysis of substrate particles before and after fungal decompositionwas also performed. Corn stalks and respectively wheat straw were mixed with 3 L of water in a laboratory bioreactor type MINIFORS. The inoculation was carried out with 300 mL Sporotrichumpulverulentum culture obtained in the rotating incubator and the action of the fungal strain on corn stalks and wheat straw was followed for 3 days in the MINIFORS bioreactor at 30 °C, 200 rpm at a flow rate of 2 L·min-1. Samples were collected and substrate mass reduction, pH, sugar content by DNS method and dry matter were analysed. The results demonstrate that the pretreatmentwith the enzymes synthesized by Sporotrichumpulverulentum in liquid medium of lignocellulosic material resulted from agricultural activities can be further used, with excellent results, in obtaining bioethanol. [ABSTRACT FROM AUTHOR]