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The regeneration of pore water (PW) nutrients was investigated and the contribution of benthic nutrient fluxes to the overlying bottom water (BW) was examined. Dissolved inorganic nutrients (

Various studies have shown the importance of using different types of Zooplankton biomasses as an additional substance in the diet of fish. In addition, the drainage water of the fish cultures could be used in plant irrigation. In this study, biomasses of water flea Daphnia magna and Gammarus pulex collected and tested, for the first time, their effect against pathogenic microorganisms and on plant germination. The results showed significant antibacterial activity of D. magna and G. pulex against Staphylococcus aureus and Pseudomonas aeruginosa bacteria, as well as antifungal activity against Alternaria solani and Penicillium expansum, which gives the possibility to be used as biocontrol against these bacteria and plant pathogenic fungi. Furthermore, both animals showed positive activity in the germination rate of Vicia faba seed, reaching 83.0 ± 3.5 and 86.0 ± 3.8%, respectively. In conclusion, the biomasses of D. magna and G. pulex are promising and effective agents for their use in the medical field against some pathogenic microbes and as stimulators of plant growth.

Citric acid is a commodity chemical mainly used as an acidulant in the food and beverage industry. In the present study, the potential use of sugar cane molasses as cheap agro-industrial waste carbon source for isolation and screening of citric acid producing microbes was investigated. Yeast isolates were obtained from soil samples, using serial dilution agar plating method and the most potent citric acid-producing isolate, coded NH-3, was identified based on macroscopic, microscopic and molecular characteristics. This strain was identified as Candida parapsilosis NH-3 and used for optimization of citric acid production using both classical and statistical methods. In classical method various parameters were investigated including: temperature, pH, molasses concentration, pre-treatment of molasses, nitrogen and phosphorus limitation and alcohol addition. Moreover, PlackettBurman design was used for further optimization. In this assay, the maximum production of citric acid was obtained at temperature 40±1° C, pH 5.0, molasses concentration 30%, pre-treatment of molasses using EDTA, nitrogen and phosphorus limitation excluding dipotassium hydrogen phosphate, and alcohol addition of 1% methanol.

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