THE INFLUENCE OF DIFFERENT PHOSPHATE AND NITRATE CONCENTRATIONS ON GROWTH, PROTEIN AND CHLOROPHYLL A CONTENT OF Scenedesmus obliquus

The growth, chlorophyll a and protein production with Scenedesmus obliquus was performed in modified Johnson's medium at initial phosphorus and nitrogen concentrations of 0.1, 0.3, 0.5, 0.7 (P) and 8, 12, 16 20 mM (N). Initial concentrations of both nutrients had a significant effect (p>0.01) on growth and contents. The highest yield (15.5 +/- 0.176 x 10(6) cell mL(-1)), chlorophyll a (10.3 +/- 0.157 mg L(-1)), and protein yields (32.3 +/- 0.323 ma L(-1)) were obtained with concentrations of 0.3 mM phosphate and 12 mM nitrate. Cell number showed significant correlations with amount of chlorophyll a (p<0.01, r = 0.97) and protein (p<0.01, r = 0.83). The medium with a 40:1 N/P ratio favored S. obliquus growth. Specific growth rates varied from 0.28 to 0.40 cell divisions d(-1)

Modelling of Scenedesmus obliquus; function of nutrients with modified Gompertz model

This study attempted to investigate variation in biovolume of Scenedesmus obliquus, in the modified Johnson medium at 20 +/- 2 degrees C, under 16 kerg cm(-2) s(-1) continuous illumination. The experiments were carried out at four nitrate (8, 12, 16, and 20 mM) and four phosphate (0.1, 0.3, 0.5 and 0.7 mM) concentrations at pH 7 and 8. The best response for algal growth was found at 0.3 mM phosphate and 12 mM nitrate at pH 7, as it was obtained from weight averaging method. Besides, optimum phosphate and nitrate concentrations significantly distinguished (p < 0.01) from other concentrations according to Tukey's HSD test. Key features of the growth of S. obliquus under phosphate and nitrate influenced batch culture was successfully predicted by modified Gompertz model. Through the cultivations, specific growth rate (p) ranged from 0.30 to 1.02 day(-1), while biovolume doubling time (td) varied from 0.68 to 2.30 days. There were important differences (p < 0.05) for both mu and td among response variables. Both nutrients displayed noteworthy effect (p < 0.01) on the algal biovolume. (C) 2008 Elsevier Ltd. All rights reserved

Relationship between soil composition, diversity and antifungal properties of Bacillus spp. isolated from southeastern Anatolia

This study examined the ecological properties, 16S rRNA definition and in vitro antagonistic effect of Bacillus spp. against Alternaria spp., Aspergillus flavus, Pseudocercospora pistacina and Septoria sp., which are destructive pathogens of pistachio nut. Bacillus spp. were isolated from rhizosphere soil samples of mined borderlines (Area I), naturally growing pistachio areas (Area II), and pistachio orchards applying standard/conventional agricultural practices (Area III). A total of 106 Bacillus spp. were isolated and 11 taxa were defined through 16S rRNA sequence analyses. Canonical correspondence analysis (CCA) was used to examine the relationship between Bacillus species and environmental variables including macro- and micro-elements, physical and chemical properties of the soil samples. The highest antagonistic activity was exhibited by B. amyloliquefaciens, B. atrophaeus, B. subtilis, B. licheniformis, and B. pumilus strains isolated from area I. Furthermore, antagonistic B. pumilus, B. mycoides, and B. amyloliquefaciens strains showed tolerance to Zn and Mn indicated by CCA. To the best of our knowledge, this is the first report on determination of alternative biological control agents and their possible use in integrated pest management strategies in pistachio orchards