Mariana Ferdes

Collagen Wound Dressings with Anti-Inflammatory Activity

The aim of this study was to develop modern wound dressings such as controlled drug delivery systems. These systems consist in collagen as release support and niflumic acid as drug. The scaffolds were prepared by lyophilization in order to obtain porous structures and were evaluated by release profile of niflumic acid, water absorption, collagenase degradation and biocompatibility with fibroblast cells. The collagen scaffold with 0.75% niflumic acid solved in laurel oil was optimal in terms of biodegradability, absorbability and fibroblast cells biocompatibility. Thus, the obtained collagen scaffolds could be used as wound dressings with absorbent, antibacterial and anti-inflammatory properties.

Modelling of sorbic acid diffusion through bacterial cellulose-based antimicrobial films

Antimicrobial packaging protects the product from the external environment and microbial contamination, conferring numerous advantages on human health. Interest in biopolymers as packaging materials has considerably increased recently. Bacterial cellulose is an interesting biomaterial produced as nanofibrils by Acetobacter xylinium and is a promising candidate due to its remarkable properties. New composite materials with antimicrobial properties were developed in this work, containing poly(vinyl alcohol) (PVA) as polymer matrix and ground bacterial cellulose (BC) as reinforcing fibres. Sorbic acid was used as an antimicrobial agent because it is a preservative recognised in the food industry. The materials obtained were studied using Fourier-transformed infrared spectroscopy (FTIR). The swelling rate of the composites was also measured. Release experiments of sorbic acid from the composite films into water were performed and the mass transfer phenomena were investigated using Fick’s law of diffusion. The antimicrobial effect was tested against Escherichia coli K12-MG1655. The results obtained indicated that the new biocomposite films could be promising antimicrobial food packaging materials.

Biostimulatory Properties of Monascus sp. Bioproducts

The therapeutic metabolites properties of microorganisms obtained from Monascus sp in solid state biosynthesis in submerged media were studied and are presented. Some products isolated from solid state biosynthesis or from submerged media, were investigated in order to establish their biological or physico - chemical properties. The primary tests performed in order to establish the antioxidant properties revealed a strong antioxidant capacity situated in the range (1420 ÷ 3700) mMol Trolox Equivalent/mg product for intracellular metabolites obtained in submerged media or in solid state biosynthesis. The immunomodulatory tests performed in vitro on a monocyte human cell line with two products isolated from solid state biosynthesis show the stimulation of human macrophage (by induction of the secretion of TNF-α and IL-6 with differentiate cell THP-1 type). The physico-chemical characteristics of investigated compounds performed by FT-IR spectroscopy show the presence of N glucosylrubropunctamine and N-glucosylmonascorubramine in biomaterials obtained by solid biosynthesis.

Cytotoxicity Study Regarding Some Products Derived from Monascus sp.

Several species of the genus Monascus produce citrinin, a mycotoxin, are harmful to the hepatic and renal systems. For this reason, the citotoxicity study is necessary to evaluate the toxicological effect of Monascus products obtained from solid state or submerged biosynthesis. In our study we evaluate the content of mycotoxin in some Monascus products and the cytotoxicity effect of them. The study regarding citrinin content revealed a content of 145 ppm citrinin in the product obtained by solid state biosynthesis, a maximum content. In the case in which the biomaterials are obtained in submerged media, in the intracellular materials, the citrinin concentration was 82,71 mg/L (or 0,827 mg citrinin/g wet Monascus biomass). In the case of extracellular product obtained in submerged media, the mycotoxin content fluctuate in the range (7 ÷ 24,5) mg/L. Study performed ‘‘in vitro’’ with product obtained in submerged media on fibroblast murine cell lines, reveals a cytotoxicity effect for concentration larger than 60 μg/ml.

Green Synthesis of Silver-Bacterial Cellulose Composites Using Turmeric Powder Extract

Abstract. Bacterial cellulose-silver (BC-silver) composites are known as biomaterials with good antimicrobial properties. The aim of this paper is to present a green route to produce antibacterial BC-silver composites using Curcuma longa tuber powder (turmeric) extract as reducing agent. The effect of medium pH and immersion time in the turmeric extract upon the silver nanoparticles was studied. The synthesis of silver nanoparticles deposited on bacterial cellulose was confirmed by ultraviolet-visible (UV-VIS) spectral studies, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX). The antibacterial activity of the nanocomposites was studied by inhibition zone method against Escherichia coli K12-MG1655, all the composites having a good antimicrobial activity.

Antioxidant Properties of Fungal Biomaterial

The antioxidant properties of methanolic extracts from extract of parental and modified Monascus sp were studied and evaluated. The fungus was inoculated into different submerged media and the produced red pigment was separated by filtration and methanol extraction from the filtrate. The antioxidant or prooxidant properties of ethanolic extract was evaluated by measuring the quenching ratio of chemiluminescence intensity. The results obtained showed a quenching ration of 87.75% for parental strain, growth 96 h in culture media with 50% maltose. The mutant strain reveals less antioxidant properties, the value of quenching ratio being 4.91%. If the growth time increased, the extract showed a prooxidant activity. At the same time the extract of mutant strain grown 96 H in the culture media containing meat extract reveals excellent antioxidant property, quantified by quenching ratio of 93.36%. When the mutant strain is grown 96 H in a culture media, which contain 30% dextrose, the methanolic extract presents an antioxidant effect with quenching ratio of 98.55%.

Identifying Microorganisms Able to Perform Biodegradation of Leather Industry Waste

Among the waste generated in leather processing, proteic and lipidic compounds are particularly dominant. Enzymes, like proteases and lipases, have an important role in biodegradation of collagen, keratin and fats in leather waste. Present investigation deals with isolation, selection and characterization of proteolytic and lipolytic microorganisms in order to perform biodegradation of waste from leather industry. The inoculum of microorganisms was sampled from old waste storage dump leather. The proteolytic microorganisms were isolated using screening method in presence of casein and gelatin substrate type, respectively. The microorganisms that secrete the lipolytic enzymes were isolated using medium that contained the Tween 80. These microorganisms identified by microscopic analysis can be used for improvement of waste leather biodegradation process.