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Background: Stress at workplace arises when the requirements for workers don’t meet their personal or social capabilities, or differ from the individual’s needs and motivation. Occupational stress is observed in a number of both elementary and high-tech occupational fields. In ferrous metallurgy it could be associated with 24/7 operating mode, high work intensity and a variety of unfavorable characteristics of working environment. The aim of the study is to clarify the nature of factors - stressors in ferrous metallurgy and to define ways for reduction of their negative health impact. Materials and Methods: Study subject are 91 workers in an electric steel-making department of a ferrous metallurgy enterprise in Bulgaria. Data, concerning working conditions, work characteristics, workers satisfaction, presence/absence of stress and chronic diseases, were collected by direct individual self-administered questionnaire and documents review. Results: Two of three study subjects reported stress related to their work. Noise, varies from 89.2 to 92.2 dB/A (at rate 85 dB/A) in different sections of the workshop, is the biggest stressor according to 77.5% of the investigated people, followed by short deadlines for task performance (46.5%) and ineffective leadership (32.4%). In addition, negative effects of stress is increasing by high dust levels, reaching up to 7 mg/m3 air at a standard of 6 mg/m3 air, and contain manganese, coke, chamotte, free and bound silica, rare metals, increased concentration of CO and more.Nevertheless workers consider that the organization provides measures for stress reduction by strict control on the limit values of noise, dust, temperature and chemicals (49.2%),provision of personal protective equipment establishment (69%) of a rational mode of work and rest (56.3%) and healthy eating (47.9%). Conclusions: Despite a plenty of environmental and organizational stressors, their negative effects could be decreased by appropriate preventive measures. Key messages: ) Factors-stressor in ferrous metallurgy could be associated with a variety of unfavorable characteristics of working environment,non-stop operating mode, high work intensity and poor time management. ) Noise is the biggest stressor followed by short deadlines for task performance and ineffective leadership. Stressors are modifiable and preventable by strict hygienic control and improved management. [ABSTRACT FROM AUTHOR]

Trametes versicolor 1 was shown to grow on phenol as its sole carbon and energy source. The culture growth and degradation ability dependence on culture medium pH value was observed. The optimal pH value of a liquid Czapek salt medium was 6.5. The investigated strain utilized completely 0.5 g/l phenol in 6 days. The dynamics of the phenol degradation process was investigated. The process was characterized by specific growth rate μmax 0.33 h−1, metabolic coefficient k = 4.4, yield coefficient Y x/ s = 0.23 and rate of degradation Q = 0.506 h−1. The intracellular activities of phenol hydroxylase (0.333 U/mg protein) and cis, cis-muconate lactonizing enzyme (0.41 U/mg protein) were demonstrated for the first time in this fungus. In an attempt to estimate the occurrence of gene sequences in T. versicolor 1 related to phenol degradation pathway a dot blot analysis with total DNA isolated from this strain was performed. Two synthetic oligonucleotides were used as hybridizing probes. One of the probes was homologous to the 5′end of phyA gene coding for phenol hydroxylase in Trichosporon cutaneum ATCC 46490. The other probe was created on the basis of cis, cis-muconate lactonizing enzyme coding gene in T. cutaneum ATCC 58094. The results of these investigations showed that T. versicolor 1 may carry genes similar to those of Trichosporon cutaneum capable to degrade phenol. [ABSTRACT FROM AUTHOR]

An extracellular acid phosphatase isolated from the culture of a wild strain Aspergillus niger, producing the dephosphorylating 3-phytase, was obtained in a homogeneous form by sequential application of ultrafiltration through PS 50 membrane, gel filtration on Sephadex G-100 and ion exchange chromatography on DEAE-Sepharose CL 6B and CM-Sepharose CL 6B. The enzyme showed a maximum catalytic value in a strongly acidic range (pH 2.0–2.4) with pHopt 2.1 and t opt 66 °C. The acid phosphatase showed a wide substrate specificity and a high affinity for sodium phytate, 2.5× higher than with 4-nitrophenyl phosphate. This property of the acid phosphatase demonstrated that it is a potent 3-phytase at pH 2.1 and is of great significance for a practical application of the dephosphorylating complex — its addition to the diets of monogastric animals in view of the low pH values in the digestive tract. [ABSTRACT FROM AUTHOR]