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Digital library of scientific journals published by Plovdiv University Paisii Hilendarski.

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Breed specific expression of gut silkworm (Bombyx mori L.) nonspecific esterases
(Plovdiv University Press "Paisii Hilendarski", 2012-05-11) Staykova, Teodora; Popov, Petar; Ivanova, Evgeniya
Nonspecific esterases of silkworm (Bombyx mori L.) gut were investigated by means of polyacrilamide gel electrophoresis (PAGE). Stage-specific expression of eleven esterase bands was detected during larval development of breeds and inter-breed hybrids kept in Bulgaria. In two esterase zones, intra- and inter-breed polymorphism was found. The polymorphism in fraction GES I1 specific for the gut may be used for testing of the breeds raised in our country with reference to determining the degree of genetic heterogeneity. The specific expression in zone GES L1 observed at present study confirmed gene determinate polymorphism in zone BES E1, observed earlier.
Molecular and phylogenetic characterization of two species of the genus Nostoc (Cyanobacteria) based on the cpcB-IGS-cpcA locus of the phycocyanin operon
(Plovdiv University Press "Paisii Hilendarski", 2012-05-11 ) Teneva, Ivanka; Stoyanov, Plamen; Mladenov, Rumen; Dzhambazov, Balik
Traditionally, the taxonomy of the genus Nostoc is based on morphological and physiological characters. The extreme morphological variability of the Nostoc species, due to their life cycle and environmental conditions, hampers the correct identification of the individual species. This is also one of the reasons for the disputed taxonomic positions and relationships between the genera Anabaena–Aphanizomenon as well as between Anabaena–Nostoc. Therefore, it is necessary to use additional markers for development of a polyphasic classification system of order Nostocales. In light of this, we here present the first molecular and phylogenetic characterization of two species of the genus Nostoc (Nostoc linckia and Nostoc punctiforme) based on the cpcB-IGS-cpcA locus of the phycocyanin operon. The phylogenetic position of these two species within order Nostocales as well as within division Cyanobacteria has been determined. Our results indicate that genus Nostoc is heterogeneous. Analysis of the IGS region between cpcB and cpcA showed that Nostoc and Anabaena are distinct genera. Reported molecular and phylogenetic data will be useful to solve other problematic points in the taxonomy of genera Aphanizomenon, Anabaena and Nostoc.
Expression of blood group antigens A and B in pancreas of vertebrates
(Plovdiv University Press "Paisii Hilendarski", 2012-05-11) Georgieva, Elenka; Sarafian, Victoria
The biological role of blood group antigens (BGA) A and B in tissues of different vertebrates is still controversial. There are few investigations on vertebrate pancreas and no obvious explanation of their tissue expression. The aim of the present study is to follow and compare the pancreatic expression of BGA A and B in representatives of five vertebrate classes. The biotin-streptavidin-proxidase labeling system was used for immunohistochemical detection of BGA by monoclonal antibodies to human A and B antigens. The present study reveals specific immunoreactivity in acinar and epithelial cells of pancreatic efferent ducts in species free-living vertebrates. The immunoperoxidase staining shows antigenic heterogeneity in the cellular localization. The number of positive cells and the intensity of expression vary in different species. Endothelial cells are positive only in the pancreas of Emys orbicularis. The lack of BGA A and B in some species suggests that the expression of these antigens is dependent not only on the evolutionary level of the species, but mainly on some genetic control mechanisms. The production of BGA A and B and the variability in their cellular localization probably reflect the stage of cell differentiation and the mechanisms of pancreatic secretor function. The presence of histo BGA in endodermal acinar pancreatic cells confirms the assumption for the high antigenic stability and conservatism of these molecules in vertebrate histogenesis and evolution.
A novel polymerase chain reaction (PCR) based assay for authentication of cell lines or tissues from human, pig and chicken origin
(Plovdiv University Press "Paisii Hilendarski", 2012-05-11) Gorenjak, Mario; Trapecar, Martin; Gradisnik, Lidija; Skok, Pavel; Cencic, Avrelija
A polymerase chain reaction based assay was developed for authentication of cell lines or tissues from human, pig and chicken origin. Specificity was achieved by species specific primer design targeting the mitochondrial D-loop sequence. Amplicon sizes were 114 bp, 169 bp and 645-648 bp for chicken, human and pig derived cell lines, respectively. Primers were tested for species specificity and non-specificity between haplogroups of the same organisms using BLAST tool and subsequently for cross amplification DNA extracted from human, chicken and pig venous blood as a positive control. Primers were also amplifying specific products in DNA extracted from individual cell line in both functional cell models and intentionally mixed cell lines consisting functional cell models. The PCR assay developed in this study represents a low-cost species specific end-point PCR based assay of the mitochondrial D-loop for the authentication of the cell line origin.
Production of cyanobacterial toxins from two Nostoc species (Nostocales) and evaluation of their cytotoxicity in vitro
(Plovdiv University Press "Paisii Hilendarski", 2012-05-12) Teneva, Ivanka; Stoyanov, Plamen; Belkinova, Detelina; Dimitrova-Dyulgerova, Ivanka; Mladenov, Rumen; Dzhambazov, Balik
Cyanobacteria are among the oldest autotrophic organisms with cosmopolitan distribution and known as producers of secondary metabolites with toxic properties named “cyanotoxins”. Studies with respect to toxin production of genus Nostoc are yet limited. In the present study we have investigated two Nostoc species (Nostoc linckia and Nostoc punctiforme) for production of intracellular and/or extracellular compounds with cytotoxic potential. Extracts and algal growth media were assessed by different in vitro tests using freshly established mouse primary cultures from different tissues and one fish cell line. Our data showed that the mouse cells are more sensitive to toxic compounds than the fish cells. Both Nostoc species produced intracellular and extracellular bioactive compounds with different effects on mouse and fish cells. The presence of cyanotoxins as anatoxin-a and microcystins/nodularin was confirmed by HPLC and ELISA analyses. Therefore, Nostoc species are not only sources of bioactive compounds with therapeutic action, but they can be a potential hazard to aquatic systems as well as to animal and human health.
Allozyme genetic polymorphism in Bulgarian honey bee (Apis mellifera L.) populations from the south-eastern part of the Rhodopes
(Plovdiv University Press "Paisii Hilendarski", 2012-05-13) Ivanova, Evgeniya; Staykova, Teodora; Stoyanov, Ivan; Petrov, Plamen
Allozyme genetic polymorphism in Bulgarian honey bee populations from four different locations in the south-eastern part of the Rhodopes Mountain was studied on six enzymic systems (MDH, ME, EST, ALP, PGM and HK) corresponding to six genetic loci. Allozyme analysis revealed that all studied loci were polymorphic in almost all investigated populations. The observed heterozygosity was found to range from 0.110 to 0.208 and Nei’s genetic distance – between 0.016 and 0.061 among the studied populations. These honey bee populations were clustered in two groups in the UPGMA dendrogram. The Tihomir population was in a separate clade while other three populations (Kardzhali, Krumovgrad and Dolni Yurutci) were grouped together.
Enzymatic production of glucooligosaccharides using dextransucrases from strains Leuconostoc mesenteroides Lm 22 and Leuconostoc mesenteroides Lm 28
(Plovdiv University Press "Paisii Hilendarski", 2012-05-17) Iliev, Ilia; Vasileva, Tonka
Dextransucrases are enzymes that transfer the glucosyl moiety from sucrose to other acceptor molecules. In the present study, we have investigated the biosynthesis of dextransucrases by two strains of Leuconostoc mesenteroides isolated from Bulgarian fermented products. Extracellular dextransucrase activities of 10.80 U/ml for strain Lm 28 and 9.6 U/ml for strain Lm 22 were measured in a batch culture. The SDS-PAGE analysis showed that the molecular weight of the dextransucrases isolated from both strains was 180 kDa. Enzymes of the studied strains were found to efficiently transfer the glucosyl moiety of sucrose onto maltose acceptor. By increasing the sucrose/maltose ratio, it was possible to catalyze the synthesis of oligosaccharides of increasing degree of polymerization.
Effects of temperature, pH-values and sodium chloride concentrations on the glucose-6-phosphate dehydrogenase activity by thermotolerant Bacillus strains
(Plovdiv University Press "Paisii Hilendarski", 2012-05-20) Aqel, Hazem; Al-Quadan, Farouk; Boulenouar, Noureddin
Thirteen new isolated thermotolerant Bacillus strains and four known Bacillus species were used to evaluate the effect of growth temperature, pH-values and NaCl concentrations on the intracellular glucose-6-phosphate dehydrogenase (G6PDH) activity. Results had shown a significant difference in G6PDH production among all species at all used temperatures (p<0.05). The response of individual new isolates and controls for production of G6PDH under growth conditions was variable. The optimal growth conditions did not correspond to the optimal cultivation conditions for maximum G6PDH production. The growth temperature showed the most significant effect on G6PDH activity. The combined effect of temperature and NaCl on the G6PDH activity was strongly pronounced in comparison with the combined effect of temperature and pH or pH and NaCl. Thermal stability at 53ºC and electrophoretic mobility were also investigated. G6PDH from HUTB41 was the most thermostable G6PDH enzyme with T50% of more than 360 minutes. Electrophoretic study demonstrated that G6PDH was composed of two isoenzymes for all strains except B. marinus and B. schlegelii that had three isoenzymes.
Environmental genotoxicity evaluation using a micronucleus test and frequency of chromosome aberrations in free-living small rodents
(Plovdiv University Press "Paisii Hilendarski", 2012-05-23) Mitkovska, Vesela; Chassovnikarova, Tsenka; Atanassov, Nasko; Dimitrov, Hristo
An in vivo micronucleus (MN) test in peripheral erythrocytes and frequency of bone marrow cells with chromosome aberrations in free-living small rodents, chronically exposed to heavy metal pollution were used for detection the genome response to genotoxic agents in the environment. Yellow-necked mice (Apodemus flavicollis), common vole (Microtus arvalis) and East-Mediterranean (Macedonian) mice (Mus macedonicus) were collected in a polluted region near lead-zinc smelting factory – Asenovgrad (South Bulgaria, near Plovdiv) and in the background region of the Strandzha National Park (Southeastern Bulgaria). Mean frequencies of MN and aberrant cells in the individuals from the impact region were significantly higher compared to the mean frequencies from the same species in the background region. The comparative analysis of results confirmed that the species Apodemus flavicollis and Microtus arvalis may be suitable bioindicators for biomonitoring studies using MN test and chromosome aberrations. Obtained results demonstrated that the in vivo MN test may be a sensitive end-point for the detection of genotoxity that may result from the simultaneous action of several metals and may be useful as a biomarker of environmental stress in situ.
Optimization and scale-up of fermentation of glucansucrase and branched glucan by Pediococcus pentosaceus CRAG3 using Taguchi methodology in bioreactor
(Plovdiv University Press "Paisii Hilendarski", 2012-05-28) Shukla, Rishikesh; Goyal, Arun
The present investigation focuses on screening and optimization of media components to enhance glucansucrase and glucan production by Pediococcus pentosaceus CRAG3 at shake-flask and bioreactor level using Taguchi orthogonal array design. A three-level Taguchi orthogonal array layout of L27 (33) was employed, in which six variables were studied for their influence on glucansucrase and glucan production. The results showed that sucrose, K2HPO4 and Tween-80 were the most significant factors to improve glucansucrase production while the glucan production was mostly affected by sucrose, peptone and K2HPO4. The optimized medium composition for maximum glucansucrase and glucan production were: sucrose 3.5% and 5%; yeast extract 0.2% and 2.0%; beef extract 0.5% and 0.5%; peptone 3.0% and 1.0%; K2HPO4 0.2% and 0.2%, and Tween-80 1.0 and 0.1%, respectively. The optimized medium gave 10.1 U/ml and 10.2 U/ml glucansucrase activity while glucan concentrations were 56 mg/ml and 80 mg/ml in shake flask and bioreactor level, respectively which were in good agreement with predicted values (10.1 U/ml and 54.5 mg/ml). The optimized medium gave 2 fold enhancement in enzyme activity and 4 fold increase in glucan concentration as compared to non-optimized medium (4.5 U/ml and 15 mg/ml, respectively) at shake flask level.
SSR marker-based molecular characterization and genetic diversity analysis of aromatic landreces of rice (Oryza sativa L.)
(Plovdiv University Press “Paisii Hilendarski”, 2012-09-20) Sajib, Abdul M.; Hossain, Md. Musharaf; Mosnaz, A.T.M.J.; Hossain, Hosneara; Islam, Md. Monirul; Ali, Md. Shamsher; Prodhan, Shamsul H.
Molecular characterization of the genotypes gives precise information about the extent of genetic diversity which helps in the development of an appropriate breeding program. In the present study, a total of 24 SSR markers were used across 12 elite aromatic rice genotypes for their characterization and discrimination. Among these 24 markers 9 microsatellite markers were showed polymorphism. The number of alleles per locus ranged from 2 alleles (RM510, RM244, and RM277) to 6 alleles (RM 163), with an average of 3.33 alleles across 9 loci obtained in the study. The polymorphic information content values ranged from 0.14 (RM510) to 0.71 (RM163) in all 9 loci with an average of 0.48. RM163 was found the best marker for the identification of 12 genotypes as revealed by PIC values. The frequency of most common allele at each locus ranged from 41% (RM163, RM590, and RM413) to 91% (RM510). The pair-wise genetic dissimilarity co-efficient indicated that the highest genetic distance was obtained between Basmati PNR 346 and Deepa; Basmati PNR 346 and Patnai-23; Dolargura and Sugandha; Bhogganijia and Sugandha; and finally between Dolargura and Chinikani (88.89%). Opchaya, Basmati PNR 346 and Sugandha had close similarity among them but showed wide dissimilarity with other genotypes. Being grouped into distant clusters Dolargura and Opchaya could be utilized as potential parents for the improvement of fine grain aromatic rice varieties. Genotypes Deepa and Patnai-23 (having zero dissimilarity) might have possessed somewhat similar genetic background and more markers are needed to discriminate them. The microsatellite marker based molecular fingerprinting could serve as a sound basis in the identification of genetically distant accessions as well as in the duplicate sorting of the morphologically close accessions.
Bacterial interference with host epithelial junctional complexes: Probiotic bacteria vs. A/E lesion-forming Escherichia coli
(Plovdiv University Press “Paisii Hilendarski”, 2012-09-27) Topouzova-Hristova, Tania; Stephanova, Elena; Stoitsova, Stoyanka
During colonization, enteropathogenic (EPEC) and enterohaemorrhagic (EHEC) Escherichia coli are capable to manipulate host cytoskeleton and colonize gut epithelia by a specific mode of attachment known as the attaching and effacing lesion (A/E lesion). While actin rearrangements during A/E lesion formation have been extensively investigated, the possible alterations of other cytoskeletal elements like those comprising the intercellular junctional complexes (JC) of polarized cells during infection have only lately attracted attention. The present mini-review addresses the opposite effects of two groups of bacteria, A/E lesion-forming pathogenic E. coli and probiotic bacterial strains, on JC. JC are important in maintaining gut barrier functions. EPEC and EHEC can disrupt JC which as a consequence leads to reduction in the transepitelial electrical resistance (TER) and an increase of the permeability to macromolecules. Probiotic bacteria on the other hand stabilize JC thus increasing TER and reducing permeability to macromolecular markers. Probiotic strains can protect JC integrity of polarized cells from the damage caused by EPEC or EHEC. Together with the promise of these results, of concern is the fact that the outcome of the studies can differ dependent on experimental protocols. Studies with living bacteria and different strain combinations have also put forward strain specific effects. Therefore, an important practical item for future studies is the identification of the molecules synthesized by probiotic bacteria that may be active on JC stability.
Recent advances in Broomrapes research
(Plovdiv University Press “Paisii Hilendarski”, 2012-09-28) Gevezova, Maria; Dekalska, Teodora; Stoyanov, Kiril; Hristeva, Tsveta; Kostov, Kaloyan; Batchvarova, Rossitza; Denev, Iliya
Orobanchaceae (broomrapes) is a morphologically diverse family of predominantly herbaceous, parasitic plants. The majority of species are facultative or obligate root parasites that subsist on broad-leaf plants, thereby depleting them of nutrients, minerals and water. The taxonomy status of the family Orobanchaceae among other flowering plants is often subject of debate. They possess only a few morphological features suitable for taxonomy purposes and yet even they are quite changeable. The variability within the species is too high and hampers the attempts to create proper determination keys. During last two decades several molecular markers were used for reevaluate taxonomy, biodiversity and phylogenetic relationships within the family. Recent investigations supported by molecular taxonomy analyses have resulted in re-definition of Orobanchaceae family. According to this classification Orobanchaceae consists of 89 genera, containing 2061 species. On the Balkans the family Orobanchaceae is represented by 3 genera: Orobanche includes 25 species; Phelipanche comprises of 9 species and some putative hybrids; Diphelypaea occurs with single species, Diphelypaea boissieri, in Macedonia and Greece. Only a few recent studies based on modern methods took place during last decade. Their findings confirmed differences between Phelipanche and Orobanche genera, but raised new question about their internal structure. Several broomrape species parasitize important crops. They are widely spread in Bulgaria, Southern Europe, Russia, Middle East and Northern Africa. They cause losses in crop productivity estimated at hundreds of millions of dollars annually than affect the livelihoods of 100 million farmers. A wide variety of approaches have been explored to control broomrapes, but none have been found to be sufficiently effective and affordable. The new findings about their life cycle and the recent genomic project focused on sequences of Ph. aegyptiaca genome open new perspectives for management of the harmful broomrape species and for understanding of their biology and evolution as well.
A novel neutral protease from thermophilic Bacillus strain HUTBS62
(Plovdiv University Press “Paisii Hilendarski”, 2012-10-15) Aqel, Hazem; Al-Quadan, Farouk; Yousef, Tahani K.
A novel neutral highly thermostable protease was detected in the culture medium of thermophilic Bacillus strain HUTBS62 isolated from hot-spring located near to the Dead Sea, Jordan. The enzyme was purified by precipitation with 55-60% ammonium sulfate, gel filtration on Sephadex G-100 and DEAE ion exchange chromatography. The enzyme was purified 53-fold with 2% yield. The optimum pH and temperature for catalytic activity of protease was pH 6.8 and 80ºC, respectively, and 31% activity of protease remained even after heat treatment at 100ºC for 60 min. The relative activity of the enzyme was highly stable (90%) at 50ºC for 2 h. The half-life of the enzyme at 90ºC, 80ºC and 70ºC was estimated to be 3, 4 and 6 h, respectively. The activation energy of denaturation of purified enzyme was 21.7 kJmol-1. Iron, sodium, calcium, and manganese increased protease activity. On the other hand, magnesium, cobalt and zinc variably decreased the residual activity. But cadmium and copper drastically inhibited the enzyme activity. The enzymatic activity was highly stable in the presence of 1 and 2 mM EDTA at pH 6.8 and 80ºC. The neutral protease therefore could be defined as a highly thermostable with new properties make the present enzyme applicable for many biotechnological purposes.
Physiological damage in Algerian mouse Mus spretus (Rodentia: Muridae) exposed to crude oil
(Plovdiv University Press “Paisii Hilendarski”, 2012-10-16) Da Silva Júnior, Flavio M.R.; Monarca, Rita I.; Dias, Deodália; Ramalhinho, Maria G.; Mathias, Maria L.; Muccillo-Baisch, Ana L.
Small mammals have been used to predict ecotoxicological damage caused by metals in field studies and laboratory exposure. In natural ecosystems, rodents play an important role either as seed dispersers or food providers for various predators since they represent intermediate links in the food chain. Several studies have already focused on the effects of metals on wild rodents, but data provided on the effects of organic contaminants, such as crude oil, are scarce. Among the possible biological indicators, physiological parameters are useful because they reflect, accurately, the organism-environment interaction. The current study aimed: I) to evaluate the effects of the exposure to soil contaminated by crude oil in the Mus spretus mice and II) to select sensitive markers to crude oil pollution. Mice collected in free-contaminated areas were exposed to artificial soil contaminated by crude oil, and compared with animals housed in artificial non-contaminated soil (control soil). External signs such as lethargy and alopecia were observed in the first days of exposure. However, no changes in animals’ body weight were recorded although changes in relative weight of some organs (liver, spleen and lungs) were observed. Furthermore, results also revealed increase in basal metabolic rate and decrease in exploratory and locomotor activity. Exposure to soil contaminated also caused dysfunction of the adrenal glands measured through fecal corticosterone levels. Data obtained highlight the relevance of using ex situ models, such as wild mice, and suggest a set of biological markers to predict and monitor environmental damage caused by crude oil exposure.
Low temperature extraction of essential oil bearing plants by liquefied gases. 7. Seeds from cardamom (Elettaria cardamomum (L.) Maton)
(Plovdiv University Press “Paisii Hilendarski”, 2012-10-25) Gochev, Velizar; Girova, Tanya; Stoilova, Ivanka; Atanasova, Teodora; Nenov, Neno; Stanchev, Veselin; Soyanova, Albena
The chemical composition of extract from the seeds of cardamom (Elettaria cardamomum (L.) Maton, obtained by extraction with tetrafluoroethane was analyzed using GC and GC/MS. The major compounds (concentration higher than 3%) of extract were: terpinyl acetate (36.8%), 1,8-cineole (29.2%), linalyl acetate (5.2%), sabinene (3.9%) and linalool (3.1%). The studied extract demonstrated antimicrobial activity against pathogenic species Staphylococcus aureus, S. epidermidis, Salmonella abony and was inactive against Pseudomonas aeruginosa. The extract possessed low antioxidant activity against DPPH radicals.
Bioremediation potential of a newly isolate solvent tolerant strain Bacillus thermophilus PS11
(Plovdiv University Press “Paisii Hilendarski”, 2012-10-31) Sarkar, Payel; Ghosh, Shilpi
The increased generation of solvent waste has been stated as one of the most critical environmental problems. Though microbial bioremediation has been widely used for waste treatment but their application in solvent waste treatment is limited since the solvents have toxic effects on the microbial cells. A solvent tolerant strain of Bacillus thermophilus PS11 was isolated from soil by cyclohexane enrichment. Transmission electron micrograph of PS11 showed convoluted cell membrane and accumulation of solvents in the cytoplasm, indicating the adaptation of the bacterial strain to the solvent after 48h of incubation. The strain was also capable of growing in presence of wide range of other hydrophobic solvents with log P-values below 3.5. The isolate could uptake 50 ng/ml of uranium in its initial 12h of growth, exhibiting both solvent tolerance and metal resistance property. This combination of solvent tolerance and metal resistance will make the isolated Bacillus thermophilus PS11 a potential tool for metal bioremediation in solvent rich wastewaters.
Study of the transgalactosylation activity of β-galactosidase from a new strain Kluyveromyces lactis 3
(Plovdiv University Press “Paisii Hilendarski”, 2012-11-12) Iliev, Ilia; Vasileva, Tonka
Beta-galactosidase (EC.3.2.1.23) is an important enzyme industrially used for the hydrolysis of lactose from milk and milk whey for several applications. Lately, the importance of this enzyme was enhanced by its galactosyltransferase activity, which is responsible for synthesis of transgalactosylated oligosaccharides that act as prebiotics with several beneficial effects on the consumers. ß-Galactosidase production by Kluyveromyces lactis 3 was studied in shake flask culture. The highest enzymatic activity was obtained at 10-th hour of the fermentation. The optimum temperature for transferase activity was 50°C. When incubated with 30% lactose in 50 mM phosphate buffer (pH 6.0) the enzyme can synthesize up to 41% galacto-oligosaccharides (GalOS). β-Galactosidase from strain Kluyveromyces lactis 3 produces mainly oligosaccharides with degree of polymerization (DP) 6 at 40°C and with DP 3 at 50°C.
Effects of carbon sources, oxygenation and ethanol on the production of inulinase by Kluyveromyces marxianus YX01
(Plovdiv University Press “Paisii Hilendarski”, 2012-11-12) Gao, Jiaoqi; Chen, Lijie; Yuan, Wenjie
Inulinase is one of the most important factors in consolidated bioprocessing, which combines enzyme production, inulin saccharification, and ethanol fermentation into a single process. In our study, inulinase production and cell growth of Kluyveromyces marxianus YX01 under different conditions were studied. Carbon source was shown to be significant on the production of inulinase, because the activity of inulinase was higher using inulin as a carbon source compared with glucose or fructose. The concentration of the carbon source had a repressive effect on the activity of inulinase. When the concentration was increased to 60 g/L, inulinase activity was only 50% compared with carbon source concentration of 20 g/L. Enzyme activity was also strongly influenced by aeration rate. It has been shown that the activity of inulinase and cell growth under anaerobic conditions were maintained at low levels, but aeration at 1.0 vvm (air volume/broth volume minute) led to higher activity. Inulinase activity per unit biomass was not significantly different under different aeration rates. Ethanol had a repressive effect on the cell growth. Cells ceased growing when the level of ethanol was greater than 9% (v/v), but ethanol did not affect the activity of secreted inulinase and the enzyme was stable at ethanol concentration up to 15%.
Biosorption of Cu (II) onto chemically modified waste mycelium of Aspergillus awamori: Equilibrium, kinetics and modeling studies
(Plovdiv University Press “Paisii Hilendarski”, 2012-11-12) Velkova, Zdravka; Stoytcheva, Margarita; Gochev, Velizar
The biosorption potential of chemically modified waste mycelium of industrial xylanase-producing strain Aspergillus awamori for Cu (II) removal from aqueous solutions was evaluated. The influence of pH, contact time and initial Cu (II) concentration on the removal efficiency was evaluated. Maximum biosorption capacity was reached by sodium hydroxide treated waste fungal mycelium at pH 5.0. The Langmuir adsorption equation matched very well the adsorption equilibrium data in the studied conditions. The process kinetic followed the pseudo-firs order model.

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