In this work we tested biopreparations developed in our laboratory for their ability to degrade the organic matter of the bottom sediments of Turawa Lake. The biodegradation was conducted under laboratory conditions for 6 weeks. For the testing purposes, there were three variants of biopreparations that contained autochthonous strains originating from our own collection and their mixture. The testing showed that the introduction of the biopreparations to the bottom sediment resulted in a significant increase of the number of bacteria, which consequently brought about the reduction of organic compounds in the sediment. In the case of all the variants, the number of bacteria increased by order of 102 - 104 CFU/g after 42 days of biodegradation. Among the tested biopreparations, the most effective one was the mixture of the autochthonous strains and those originating from the collection. After biopreparation was applied, a drop of content of carbohydrates by 66.94%, fatty matter by 83.33% and proteins by 74.42% was noted.
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In these studies we attempted to evaluate the lipolytic, proteolytic and cellulolytic activity of bacterial strains isolated from water and the bottom sediments of Turawa Lake. The following bacterial genera prevailed among the isolated strains: Bacillus, Pseudomonas, Enterobacter, Cellulomonas and Cytophaga. The lipolytic activity was determined using a titrimetric method, the proteolytic activity - using a modified Anson method, and the cellulolytic activity - on the basis of mass decrement of a cellulose disk after 14 days of bacterial culture. The cultures were maintained at 28°C, pH 7.0 with the following substrates: olive oil, albumin and cellulose disk. Among the analysed microorganisms, Bacillus and Pseudomonas strains showed the highest lipolytic and proteolytic activity. In the cellulolytic assay Cytophaga bacteria showed about twofold higher activity than that of Celulomonas.
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The optimum conditions for biosorption of Pb(II) and Ni(II) from aqueous solution were investigated, by using living and nonliving Pseudomonas fluorescens and Bacillus pumilus isolated from wastewater treatment plant. It was found that the optimum pH for Pb(II) removal by living and nonliving cells was 6.0, while 7.0 for Ni(II) removal. At the optimal conditions, metal ion biosorption was increased as the initial metal concentration increased. The binding capacity by living cells is significantly higher than that of nonliving cells at tested conditions. The maximum biosorption capacities for lead and nickel by using Ps. fluo-rescens and B. pumilus were 77.6, 91.4 and 65.1, 73.9 mg/g, respectively. The results of bio-sorption time and desorption experiments suggested that Pb(II) and Ni(II) uptake by the living bacterial biomass might be enhanced by intracellular accumulation.
The term "allelopathy" was introduced to science in 1937 by Hans Molisch, who used the concept of allelopathy to identify negative impact of chemicals secreted by a plant on the growth of other neighboring plants. In 1996, the International Allelopathy Society has broadened the meaning of allelopathy as any inhibitory or stimulatory process in which chemical substances secreted by various organisms interact with their ecosystem. Allelopathy may be one of the factors contributing to formation and maintenance of cyanobacterial and algal blooms, which strongly affect coastal marine ecosystems and cause economic problems for commercial aquaculture. A better understanding of the complexity and nature of underlying allelopatic interactions may help to explain the emergence of massive blooms of cyanobacteria and algae in many aquatic ecosystems.
Sinice pikoplanktonowe stanowią podstawowy element ekosystemów wodnych, występując zarówno w zbiornikach słodkich, brakicznych, jak i otwartych wodach oceanicznych. Pełnią one kluczową rolę w produkcji pierwotnej, a ich największy udział notuje się w wodach oligotroficznych. Jednak dotychczasowe informacje na temat tych organizmów wciąż pozostają niewystarczające. W ostatnich latach wzrosła liczba doniesień dotyczących masowych zakwitów sinic pikoplanktonowych, ich potencjalnej toksyczności, a także szkodliwego wpływu na całe ekosystemy wodne. Dokładne poznanie mechanizmów odpowiedzialnych za ekspansję tych wodnych fotoautotrofów jest niezwykle ważne dla lepszego zrozumienia funkcjonowania środowiska morskiego. W pracy podsumowano dotychczasowy stan wiedzy na temat sinic pikoplanktonowych oraz przybliżono najnowsze informacje potwierdzające ich zdolność do tworzenia masowych zakwitów w wielu ekosystemach wodnych.
EN
Picocyanobacteria are common in freshwater, brackish and marine ecosystems throughout the world. They play an essential role in primary production and their domination in phytoplankton biomass is common particularly in oligotrophic waters. However, this group of photoautotrophic organisms still remains insufficiently investigated. The number of works on the occurrence of massive blooms of picocyanobacteria, their role in aquatic habitats and potential toxicity has notably increased in last years. Filling existing gaps in the knowledge of mechanisms responsible for the global expansion of these organisms can provide a better understanding of functioning of the aquatic environments. In this review, we summarized the most recent information concerning picocyanobacteria and the occurrence of their massive blooms in many aquatic ecosystems.
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