Mohamed E.H. Osman

Growth and heavy metals removal efficiency of Nostoc muscorum and Anabaena subcylindrica in sewage and industrial wastewater effluents

The growth of Nostoc muscorum and Anabaena subcylindrica in sterilized sewage wastewater and N. muscorum in sterilized wastewater of El-Soda Company was higher than those grown in Allen synthetic medium. Whereas, the growth of A. subcylindrica in El-Soda Company sterilized wastewater and N. muscorum as well as A. subcylindrica grown in Verta Company sterilized wastewater was slightly lower than that grown in the standard synthetic medium. The contents of chlorophyll a, carotenoids and protein of N. muscorum and A. subcylindrica grown in sterilized sewage wastewater were higher than those grown in the standard medium. Similarly, N. muscorum and the bio-mixture of N. muscorum and A. subcylindrica grown in the sterilized wastewater of El-Soda Company showed high pigments and protein contents more than those reared in Allen medium. On the other hand, the bio-mixture of N. muscorum and A. subcylindrica grown in the sterilized sewage wastewater, A. subcylindrica grown in El-Soda Company and Verta Company sterilized wastewater showed lower contents of pigments and protein compared to synthetic medium. Heavy metals, copper, cobalt, lead and manganese were removed by 12.5-81.8, 11.8-33.7, 26.4-100 and 32.7-100%, respectively, from wastewater by using cyanobacterial cultures. The metal sorption efficiency depended on the type of biosorbent, the physiological state of the cells, availability of heavy metal, concentration of heavy metal and chemical composition of wastewater. It was observed also that the single cultures in most cases was better than the mixed cultures in heavy metal removal, this may be due to the cyanobacterial competition for nutrients in mixed cultures.

Effect of cobalt on growth, pigments and the photosynthetic electron transport in Monoraphidium minutum and Nitzchia perminuta

The unicellular green alga Monoraphidium minutum and the diatom Nitzschia perminuta were cultured under different concentrations of Co2+. Growth and pigment content were slightly increased at low concentrations and inhibited by high Co2+ concentrations. The results concerning the effect of different concentrations of Co2+ on photosynthetic O2 evolution showed a reduction in the amount of O2 evolved by each alga in response to increasing Co2+ concentrations. However, an increase in O2 evolution for both M. minutum and N. perminuta was observed at relatively low Co2+ concentrations. Photosynthetic electron transport in M. minutum was more sensitive to Co2+ toxicity than in N. perminuta. On the other hand, the effect of the heavy metal on respiration showed that higher Co2+ concentrations were inhibitory to O2 uptake by the two algal species. Low Co2+ concentrations stimulated O2 uptake by M. minutum throughout the experimental period. However, in N. perminuta, different concentrations of Co2+ led to a reduction of O2 uptake. To localize the action site of Co2+ in the photosynthetic electron transport chain, the fluorescence induction technique was carried out. According to the results obtained, the inhibitory action of Co2+ is located on the acceptor side of PSII for both M. minutum and N. perminuta.

Production and characterization of antimicrobial active substance from the cyanobacterium Nostoc muscorum.

In this investigation, the cyanobacterium Nostoc muscorum exhibited antagonistic activity against Gram-positive and Gram-negative bacteria and filamentous fungi. The results indicated that the active substance produced maximally after 12 days of incubation in shaken culture at 35°C, at pH 8.0 in BG-11 medium. The increase in nitrate concentration of the medium led to an increase in the antimicrobial production. Chloroform was the best solvent for extracting the active material. The antagonistic material was purified using thin layer chromatography. The compound showed maximum absorption at 240nm. Infrared (IR) and nuclear magnetic resonance (NMR) indicated presence of γOH, γCH aromatic, γCH aliphatic, γCN, γCO, γCC and CO. Mass spectroscopy indicated that its molecular weight is 279. The results also indicated that the compound is phenolic compound.

Photosynthetic performance and adaptation of sugarcane at suboptimal temperatures

Summary Cultivation of sugarcane is limited by moderate chilling temperatures of 15° in subtropical areas of the world, whereas high temperatures seem to pose less problems. To obtain an overview of the physiological parameters affected, sugarcane plants were grown at 15, 27, and 45° for up to 10 months and photosynthetic parameters of the leaves were determined, namely chlorophyll content, Hill reaction, chlorophyll fluorescence parameters concerning photosystem II and electron transport activity, and critical temperature of chloroplast membrane organization. In all cases plants grown at 27° were superior to those grown at 15 or 45°. The photosynthetic performance of plants grown at 45° was superior to those grown at 15° in all parameters, when the plants were young (3 months old). With age some adaptation to the unfavourable temperatures proceeded, indicated by a change of photosynthetic properties in the direction of plants grown at optimal temperature (27°). The adaptation was especially strong for the plants grown at 15°, so that after 9 months their performance was better than that of 45° plants. The conclusions for breeding of more temperature adapted sugarcane plants are discussed.

Differential effects of Co2+ and Ni2+ on protein metabolism in Scenedesmus obliquus and Nitzschia perminuta

Growth, morphological changes, amino acid composition, total soluble protein, and protein electrophoretic pattern were monitored for Scenedesmus obliquus and Nitzschia perminuta grown in the presence of different concentrations of Co(2+) and Ni(2+). Lower concentrations of cobalt stimulated the dry mass production and total soluble protein content of the two algae, whereas higher concentrations were inhibitory. Generally, N. perminuta showed more tolerance to the phytotoxicity of the two metals than S. obliquus and more tolerance to nickel than cobalt. However, S. obliquus seems to be more tolerant to cobalt than nickel. Cobalt and nickel have induced an increase in cell volume, change and disorder in cell shape. The increase in cell volume was much observed in Ni(2+) treated cells. At the same time, the two metals did not induce any distinct morphological abnormalities in N. perminuta. Co(2+) has stimulated the biosynthesis of all free amino acids in S. obliquus, except aspartic acid and phenylalanine, whereas Ni(2+) caused 22% inhibition in the content of total free amino acids, except cystine and arginine. On the other hand, Co(2+) has reduced the content of free amino acids in N. perminuta, except cystine, methionine, valine, and lysine. On the other hand, Ni(2+) stimulated the biosynthesis of glycine, alanine and histidine and highly stimulated valine and sulphur containing amino acids (cystine and methionine) in N. perminuta. High cobalt concentration (4ppm) resulted in the disappearance of 28.7kDa protein, 3.5ppm Ni(2+) stimulated the appearance of 18 and 20kDa proteins in S. Obliquus, while 37kDa proteins disappeared from N. perminuta treated with high doses of Co(2+) and Ni(2+).

Effect of two species of cyanobacteria as biofertilizers on some metabolic activities, growth, and yield of pea plant

Two cyanobacterial species (Nostoc entophytum and Oscillatoria angustissima) were tested as biofertilizers, substituting the normally used chemical fertilizer, for pea plant. Inoculation of soil with a suspension of each species or a combination of the two species significantly increased the germination percentage and stimulated the other measured growth parameters and photosynthetic pigment fractions of pea. However, the soil inoculation with one cyanobacterial species and the addition of the recommended dose or half the recommended dose of chemical fertilizer were usually more effective and also increased carbohydrate and protein contents of produced pea seeds. However, biofertilization combined with half the recommended dose of the chemical fertilizer was usually more effective than the addition of the full rate of the chemical fertilizer, and this may allow saving 50% of the used chemical fertilizer. The protein profile of the produced seeds showed appearance and disappearance of some protein bands in response to fertilization treatments compared to the control. Blue green algae analyses show that N. entophytum fixed more N, produced more exopolysaccharide, and contained more auxin and cytokinin than O. angustissima, the latter contained more gibberellins. These data may explain their different influences on growth and yield of pea.

Comparative studies on the green algae Chlorella homosphaera and Chlorella vulgaris with respect to oil pollution in the river Nile.

The effect of oil pollution on growth and metabolic activitiesof the fresh water algae Chlorella homosphaera and C.vulgaris was studied. The study was conducted on two locationsin the river Nile, one is oil polluted and the other is notpolluted. The assemblage of the different algal groups wasmonitored in both locations. Chlorophyta was more dominant thanCyanophyta and Bacillariophyta in both locations during allseasons except in winter when Bacillariophyta is the mostdominant group. The presence of crude oil or its refineryproducts (solar and lubricating) in the culture media of algaemarkedly influenced their growth, proteins and nucleic acidcontents. The toxicity of oil was a concentration dependent. Thelow concentrations stimulated growth, protein content andnucleic acids, whereas high concentrations had an inhibitoryeffect. Although DNA and RNA responded similarly to crude oil inthe two tested organisms, DNA showed more sensitivity than RNAto solar oil. Lubricating oil had a little phytotoxic effect onnucleic acids. Different species of algae response differentiallyto oil pollution; Chlorella vulgaris can be referred to asoil-sensitive, while Chlorella homosphaera can toleraterelatively higher concentrations of oil.

Mixotrophic and heterotrophic growth of some microalgae using extract of fungal-treated wheat bran

BackgroundIn this study, wheat bran, an agricultural waste, was utilized as a low-cost carbon source for algal cultivation.ResultsTreatment of lignocellulosic waste by two fungal species (Pleurotus ostreatus or Trichoderma viride) caused the accumulation of reducing sugar at a relatively high concentration (50.58 and 54.30 mg/g wheat bran) after 7 days of incubation, respectively. The soluble products of treated wheat bran increased the growth, carbohydrate, and protein contents of both Chlorella vulgaris and Scenedesmus obliquus under mixotrophic and heterotrophic conditions.ConclusionsThe obtained data suggest that soluble product of treated wheat bran could be used as an efficient medium for the mixotrophic and heterotrophic growth of both algal species.

Effect of ultraviolet irradiation on germination and growth in Aspergillus flavus and Penicillium notatum

Uv-A (366 nm) irradiation delayed germination of conidia in Penicillium notatum and Aspergillus flavus. The inhibitory effect was dependent on the exposure period and maximum inhibition was obtained after irradiation for 4 h. The length of developed germtubes was reduced by the same treatment. Uv-B irradiation (240–280, peak 254 nm) was more effective than uv-A. Irradiation for 30 min completely inhibited conidial germination in P. notatum while 40 min exposure caused complete inhibition in A. flavus. The development of germ-tubes was very slow after uv-B irradiation. Linear growth was also affected by uv-A especially if irradiation was applied for long periods. Retardation in linear growth was most pronounced during the first 3 d incubation. Uv-B irradiation markedly affected growth and a delay of 72 h in growth could be observed in some treatments. Uv-B irradiation for 4 h completely inhibited growth of P. notatum, while the same treatment retarded growth to some extent in A. flavus.

Cyanobacterial Arthrospira (Spirulina platensis) as safener against harmful effects of fusilade herbicide on faba bean plant

Treatment of faba bean plant by fusilade herbicide (post-emergence herbicide) caused reduction in all measured growth parameters (plant height, root and shoot length, number of leaves/plant, fresh and dry weight of root and shoot and leaf area) and yield parameters (number of pods/plant, number of seeds/pod, number of seeds/plant and weight of 100 seeds). Priming of faba bean seeds in Arthrospira (Spirulina platensis) suspension before cultivation ameliorated the adverse effects of the herbicide on the plant. Algal suspension treatment caused enhancement in protein and amino acid levels of root and shoot, and ameliorated also the harmful effects of the herbicide on the antioxidant enzymes and reduced the lipid peroxidation and proline content of the plant. The treatment caused marked changes in the profile of amino acids and their concentrations in leaves. The most changes were observed in leucine, isoleucine, valine, serine, phenylalanine, methionine and histidine. The concentrations of these amino acids were reduced in response to herbicide application, while increased in response to algal treatment. According to these results, priming of seeds in the Arthrospira platensis suspension induced the biosynthesis of some amino acids which could protect or act as a safener against the adverse effects of the herbicide on the plant.