The effect of various factors on dye decolorization activity of crude laccase enzyme from repeated-batch culture of Funalia trogii ATCC 200800 to obtain rapid and high decolorization activity against Reactive Black 5 and Reactive Blue 171 dyes was investigated. All conditions used were important for dye decolorizing activity of this crude laccase enzyme. The optimum pH of decolorization was tested at 30 °C and it was around 3.0. This activity was highly reduced at pH 4.5-6.0. On the other hand, the optimum temperature for rapid and high decolorization was 50 °C. Importantly, the decolorization rate of crude laccase at pH 4.5 and pH 6.0 increased with the rise in temperature from 30 °C to 50 °C. Therefore, high decolorization could be obtained at pH 4.5 and even pH 6.0 by selecting the proper temperature for these pH values. Enzyme amount also affected the dye decolorization positively. This crude laccase could also decolorize the mixed dyes (Reactive Black 5 and Reactive Blue 171) and synthetic wastewaters. Native polyacrylamide gel electrophoresis showed the responsibility of the laccase enzyme in decolorization. Rapid and high textile dye decolorization through the selection of appropriate conditions could facilitate the development of more economical and environmentally friendly processes.

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Clean and safe water is fundamental for human and environmental health. Traditional remediation of textile dye-polluted water with chemical, physical, and biological processes has many disadvantages. Due to this, nano-engineered materials are drawing more attention to this area. However, the widespread use of nano-particles for this purpose may lead to photocatalytic degradation of xenobiotics, while increasing the risk of nano-particle-induced ecotoxicity. Therefore, we comparatively evaluated the toxicity of novel synthesized core@shell TiO and SiO nano-particles to embryonic stages of Danio rerio and Xenopus laevis. The ability of photocatalytic destruction of the synthesized nano-particles was tested using toxic azo dye, disperse red 65, and the effects of reducing the toxicity were evaluated. The reflux process was used to synthesize catalysts in the study. The samples were characterized by scanning electron microscopy, X-ray fluorescence spectroscopy, X-ray diffractometry, BET surface area, and UV-vis-diffuse reflectance spectra. It was determined that the synthesized nano-particles had no significant toxic effect on D. rerio and X. laevis embryos. On the other hand, photocatalytic degradation of the dye significantly reduced lethal effects on embryonic stages of the organisms. Therefore, we suggest that specific nano-particles may be useful for water remediation to prevent human health and environmental impact. However, further risk assessment should be conducted for the ecotoxicological risks of nano-particles spilled in aquatic environments and the relationship of photocatalytic interaction with nano-particles and xenobiotics.

The aim of the study is to examine the opinions of preservice science teachers concerning the nature of science and to determine whether or not the preservice teachers' opinions differ according to their academic level. A total of 242 preservice science teachers, who studied in the Education Faculty of Inonu University, Turkey, during the 2013-2014 academic year took part in the study. In order to evaluate the opinions of the preservice teachers, eight questions from the Questionnaire of Opinions for Technology and The Nature of Science were used. The original questionnaire is comprised of 20 questions chosen from a larger questionnaire called Opinions Concerning Science, Technology and Society, developed by Aikenhead, Fleming, and Ryan (1989) empirically, and consists of eight categories and 114 multiple-choice questions, and was translated and then adapted into Turkish by specialists in the field. The data obtained were analyzed by means of SPSS 21.0 Statistics program. In analysis of the data, the frequency and percentages were checked and x-square test applied. At the end of the research, it was detected that candidate Science teachers hold a realistic point of view as to the changeability of scientific knowledge, an acceptable point of view as to the definition of science, the interaction of science and technology, and the effect of science and technology on solving social problems.On the other hand, they have an insufficient point of view as to the epistemological condition of hypotheses, theories, laws, and scientific knowledge. According to the academic level factor, it was detected that there was an effect of science and technology on solving social problems, and a dramatic difference as to the epistemological condition of hypotheses, theories, laws, and scientific knowledge. However, there was no dramatic difference seen in terms of the questions on the definition of science, the interaction between science and technology, the changeability of scientific knowledge, and the epistemological condition of scientific knowledge.

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