Hacı Halil Bıyık

Bio: Hacı Halil Bıyık is an academic researcher from Adnan Menderes University. The author has contributed to research in topics: Fermentation & Microorganism. The author has an hindex of 5, co-authored 14 publications receiving 74 citations.

Phenotypic and Genotypic Characterization of Bacteriocins in Enterococcal Isolates of Different Sources

Abstract: A collection of 57 enterococcal isolates from different origin (including river, treatment plant, spring and garbage water, soil, animal, and vegetables from Aydin) was screened for the production of bacteriocins. Enterococci were identified at species levels as Enterococcus faecium (34), E. hirae (6), E. casseliflavus (4), E. durans (4), E. faecalis (4), E. mundtii (3) and E. avium (2). Of the 57 isolates 40 of them inhibited the growth of at least one indicator bacterium. Based on our PCR results 54 strains possesed enterocin genes. The genes of entA and entB were the most frequently detected structural genes among the PCR positive strains (54 and 53 strains, respectively) and the entB gene was always associated with entA gene. The highest combination of enterocin genes (24 of 54 strains) detected was entA, entB, entP and entL50A/B. The enterocins AS-48 and CylLLS genes were not found. Three enterococcal isolates, 2 E. faecium and 1 E. hirae were not harbour any of tested enterocin genes. No correlation between the presence of enterocin structural genes and the origin of the strain was detected, also no relationship seemed to exist between the tested enterocin genes and the activity spectra of isolates. Genes encoding bacteriocins are widely disseminated among enterocci from different origin and more studies should be done for evaluate industrial potential of bacteriocins. Electronic supplementary material The online version of this article (doi:10.1007/s12088-011-0143-0) contains supplementary material, which is available to authorized users.

Characterization of an Alkaline Thermostable Pectin Lyase from Newly Isolated Aspergillus niger _WHAK1 and Its Application on Fruit Juice Clarification

Abstract: Pectin lyase degrades pectic substances that are complex polysaccharides of middle lamella and primary cell walls of plants. In this study, alkaline thermostable pectin lyase from Aspergillus niger strain_WHAK1 was produced on wheat bran and citrus pectin in submerged culture. Pectin lyase was purified by ammonium sulfate fractionation, gel filtration and ion-exchange chromatography, and 76.5 purification fold was obtained. Optimum pH and temperature values of pectin lyase were 8.0 and 40°C at 60min, respectively. The enzyme was stable for 17 months at 4°C. Km and Vmax values were found to be 5.2mg/mL and 0.2(mmol/min)−1 mL, respectively. Molecular weight of pectin lyase was nearly 23.3 kDa. Effects on PL activity of metal ions (NaCl, KCl, CaCl2, MgCl2, CoCl2, CuCl2.H2O, FeCl3.6H2O, ZnSO4.7H2O, (NH4)2SO4, MnSO4), amino acids (l-tryptophan, l-cysteine hydrochloride monohydrate, l-arginine monohyd rate), ascorbic acid, citric acid monohydrate, EDTA and resorcinol were studied. The presence of FeCl3, CaCl2 and ascorbic acid significantly enhanced relative pectin lyase activity (%). The purified pectin lyase induced viscosity reduction in fruit juice samples, and it was effective for clarification of fruit juices. Pectin lyase showed substrate preference against fruit juice samples.

Isolation and Characterization of a Bacteriocin-Like Substance Produced by Geobacillus toebii Strain HBB-247

Abstract: A total of 201 thermophilic bacteria isolated from various thermal spring, mud and soil were tested for their antibacterial activity. Among the mostly active isolates, Geobacillus toebii HBB-247 was further examined. Bacteriocin-like inhibitory substance (BLIS) produced by strain HBB-247 was found to be stable up to 60°C, sensitive to proteolytic enzymes and effective against Enterococcus faecalis, Listeria sp., E. avium, Clostridium pasteurianum, Cellulomonas fimi and some thermophilic strains isolated and identified in this study. As a result of Tricine-SDS-PAGE molecular weight of BLIS was estimated about 38 kDa. Production studies showed that G. toebii HBB-247 starts to produce antibacterial substance at early logarithmic phase of growth and maximum production was detected at the end of the logarithmic phase.

Optimization of fermentation parameters for high-activity inulinase production and purification from Rhizopus oryzae by Plackett–Burman and Box–Behnken

Abstract: The aim of study was to optimize fermentation parameters for inulinase production from Rhizopus oryzae by a statistical approach and to carry out purification of inulinase Five isolated fungal strains were screen out inulin degradation by using Lugol’s iodine solution R oryzae exhibited maximum zone of clearance around the colony and was used as an inulinase producer The effect of carbon sources (inulin, glucose, maltose, sucrose, lactose, onion peel, stevia root, wheat bran) as medium component and fermentation parameters (temperature (25–45 °C), initial pH (4–7), time (3–7 days)) on inulinase production was investigated by Plackett–Burman Design Wheat Bran (WB), temperature, pH, and incubation time were found to be significant for the production of inulinase (P < 005) Furthermore, Box–Behnken Design was employed to optimize fermentation conditions The maximum experimental results for inulinase activity and specific activity were 34836 EU/mL and 362178 EU/mg, respectively The results were obtained at 5 days of incubation time, 35 °C of incubation temperature, initial pH of 55, and 2% (w/v) WB Also, inulinase was purified by using ammonium sulfate precipitation, gel filtration chromatography with 219-fold and its molecular weight was found as 8912 kDa The optimal pH and temperature of the purified enzyme were 40 and 60 °C, respectively Furthermore, the purified enzyme showed excellent stability at 60 °C In conclusion, the present study offers cost-effective method to produce inulinase from Rhizopus oryzae Also, it can be suggested that the purified inulinase has strong potential for usage in production of fructose syrup and other industrial areas

Guidance on the characterisation of microorganisms used as feed additives or as production organisms

Abstract: [Table: see text]. Abstract This guidance document is intended to assist the applicant in the preparation and the presentation of an application, as foreseen in Article 7.6 of Regulation (EC) No 1831/2003, for the authorisation of additives for use in animal nutrition. It specifically covers the characterisation of microorganisms used as feed additives or as production organisms.

Scientific Opinion on the update of the list of QPS-recommended biological agents intentionally added to food or feed as notified to EFSA

Abstract: EFSA is requested to assess the safety of a broad range of biological agents in the context of notification for market authorisation as sources of food and feed additives, food enzymes and plant protection products. The qualified presumption of safety (QPS) assessment was developed to provide a harmonised generic pre-assessment to support safety risk assessments performed by EFSA's scientific Panels. The safety of unambiguously defined biological agents (at the highest taxonomic unit appropriate for the purpose for which an application is intended), and the completeness of the body of knowledge are assessed. Identified safety concerns for a taxonomic unit are, where possible and reasonable in number, reflected as ‘qualifications’ in connection with a recommendation for a QPS status. The list of QPS recommended biological agents was reviewed and updated in the current opinion and therefore becomes the valid list. The 2016 update reviews previously assessed microorganisms including bacteria, yeasts and viruses used for plant protection purposes following an Extensive Literature Search strategy. The taxonomic units related to the new notifications received since the 2013 QPS opinion, were periodically evaluated for a QPS status and the results published as Statements of the BIOHAZ Panel. Carnobacterium divergens, Lactobacillus diolivorans, Microbacterium imperiale, Pasteuria nishizawae, Pediococcus parvulus, Bacillus flexus, Bacillus smithii, Xanthomonas campestris and Candida cylindracea were recommended for the QPS list. All taxonomic units previously recommended for the 2013 QPS list had their status reconfirmed as well their qualifications with the exception of Pasteuria nishizawae for which the qualification was removed. The exclusion of filamentous fungi and enterococci from the QPS evaluations was reconsidered but monitoring will be maintained and the status will be re-evaluated in the next QPS Opinion update. Evaluation of bacteriophages should remain as a case-by-case procedure and should not be considered for QPS status.

Occurrence of antilisterial structural bacteriocins genes in meat borne lactic acid bacteria

Abstract: The ability to inhibit the growth of Listeria cells and the presence of bacteriocin encoding genes was examined in 115 LAB strains isolated from Argentinean vacuum-packaged beef and different traditional fermented sausages. Lactobacillus (L) sakei, Lactobacillus (L) curvatus and Enterococcus (E) faecium showed a great inhibition of all Listeria strains evaluated while Pediococcus (P) acidilactici and Lactobacillus (L) plantarum demonstrated a limited or absent antilisterial activity. Both L. curvatus and L. sakei carried the sppA, sppQ and sapA structural genes, encoding for sakacin P, sakacin Q and curvacin A bacteriocins, respectively. Whilst L. curvatus exhibited a higher occurrence of these genes, L. sakei strains were more effective at inhibiting Listeria (L) strains, Listeria monocytogenes UC8159 and Listeria innocua 7 being the most sensitive to these bacteriocins. Among analyzed E. faecium strains, the wide distribution of entA, entB and entP genes accounted for the high antilisterial activity particularly observed against L. monocytogenes FBUNT. The structural gene plantEF was mostly present in Lactobacillus plantarum strains and no pedA gene was found in P. acidilactici evaluated strains. The antilisterial potential of L. sakei and E. faecium offers great possibilities for the meat industry as biopreservative cultures, although more studies are needed in order to conclude about this issue.

Biodiversity and technological-functional potential of lactic acid bacteria isolated from spontaneously fermented quinoa sourdoughs

Abstract: Fil: Ruiz Rodriguez, Luciana Gabriela. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina