GLUCOSE ADDITION AND FUNGI INOCULATION IN SOIL, COMPARED WITH MULTIVARIATE STATISTICAL

COSTA, B.O1, BRAZ, R.R.2, TAVARES, R.L.M.3, NAHAS, E.4

1,2,4

Depto. de Produção Vegetal –Universidade Estadual Paulista “Julio de Mesquita Filho”, Jaboticabal/SP

1_{beatriz.oliveira.costa@hotmail.com}

3 _{Depto. de Solos, Universidade Estadual de Campinas. Av. Cândido Rondon 501. Barão Geraldo.} Campinas/SP.

Keywords: multivariate analysis, soil fungi, soil microbiology

In search of soil nutrients, strong competition occurs between the microorganisms saprophytic and pathogenic species (Grodnitskaya and Sorokin, 2007). Among the fungi community, influencing several pathogenic agents that cause plants and seeds diseases (Long, 2002; Felix, 2007). Due to these diseases, significant losses occur in agriculture and may even limit the cultivation of different plant species of economic interest. The aim of this study was to introduce in the soil, fungi isolated from the seeds, Aspergillus flavus,

Fusarium verticillioides, Penicillium sp. and these development in two soil types. Were

selected soils from two areas located in Jaboticabal city, SP: native forest, where the soil was classified as Eutrophic Oxisol – LVE, and an annual crop area, where the soil was classified as Dystrophic Oxisol – LVD, classification according to Embrapa (2006). The fungi obtaining and cultivation were by BDYA medium (Kucey, 1983), distributed in test tubes, for multiplication of these, isolated from corn seeds. The inoculum was suspended in distilled water and counted in a Neubauer chamber, with a total of 1,175 x 106 spores / g dry soil. For the Petri dishes assembly, 62 g soil were weighed and transferred to each plate and moisture balanced to 60% of Water Holding Capacity. The solutions were prepared by adding 2.32 mL of the fungus concentrate, plus 27.28 g of glucose, when treatment involved the addition of glucose, and then turned up the volume with distilled water to 660 ml (LVD) and 748 mL (LVE). On each plate, were added 15 and 17 mL respectively for LVD and LVE. After this procedure, the plates were incubated for a period of 21 days, with all treatments separated by incubator without light and temperature controlled at 25°C. Separately for each soil, the treatments were obtained through a factorial 4 x 2. Was considered the multivariate statistical analysis, because of complex attributes. Used the Euclidean distance as a measure of similarity between sampling units and cluster analysis was performed by connecting simple. Clear difference was noted in three groups at multivariate analysis, observed in which, the soil distinction and glucose addition. In group one, fertile soil and natural vegetation (LVE), all with the glucose addition, Penicillium sp. showed a very close resemblance of Aspergillus flavus than Fusarium verticillioides, and the control seems a little off the fungi inoculated. The other groups (two and three) showed the same behavior described in one group. The glucose addition influenced the fungi development in most cases. However, the fungus Fusarium verticillioides doesn’t seem to be influenced by the glucose addition.

Financial support: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

GLUCOSE PROFILE ON CULTIVATION OF Aphanothece microscopica

Nägeli IMMOBILIZED IN CALCIUM ALGINATE BEADS

MATOS, V. C. ¹*, BASTOS, R. G.¹

¹Centro de Ciências Agrárias, Universidade Federal de São Carlos, Rodovia Anhanguera, Km 174. Araras – SP. * victorcarmatos@gmail.com

Keywords: cyanobacterium, Aphanothece microscopica Nägeli, alginate beads, glucose profile

The use of cyanobacteria in biotechnology has been increased in recent years in food, cosmetic, aquaculture and pharmaceutical industries. Moreover, several strains of have been used on wastewater treatment, mainly for nutrient removal. Since the size of single cells implies a problem in the application of these organisms on biotechnology processes, cell immobilization techniques have been developed in order to solve those questions. Indeed, the use of immobilized cyanobacteria cells in water purification processes has been reported from long ago. Most of the immobilization techniques devised for microorganisms in general can be applied to microalgae, with the limitation of light transmission to living cells. Aphanothece microscopica Nägeli is a cyanobacteria that has been studied with a view to the valorization of agro-industrial wastewater, production of single-cell protein and CO2 removal in tubular photobioreactors. However, there is a little

previous study about immobilization of these cyanobacteria. Thus, the aim of this research was evaluate the glucose profile at cultivation of Aphanothece microscopica Nägeli immobilized on calcium-alginate beads by gel entrapment technique. Particles with average diameter 4mm containing 106cell/mL were submerged in vinasse and BGN medium with glucose. Data suggests glucose quasi-depletion in vinasse after ten hours, with a slight decrease of particle size during the experiments. Results indicate the feasibility of immobilization of Aphanothece microscopica Nägeli and heterotrophic growth with glucose uptake, consisting an alternative for continuous organic removal by cyanobacteria.

GROWTH OF Aphanothece microscopica Nägeli AND Chlorella vulgaris AT VARIOUS GLUCOSE CONCENTRATIONS IN MIXOTROPHIC CULTURES

BONINI, M.A.1*, BASTOS, R.G.2

1*

Programa de Pós Graduação em Agricultura e Ambiente, Centro de Ciências Agrárias (CCA), Universidade Federal de São Carlos (UFSCar), Rodovia Anhanguera km 174, Araras – SP. *monicabonini@ig.com.br

2*_{Depto. de Tecnologia Agroindustrial e Sócio-Economia Rural, CCA, UFSCar.}

Keywords: microalgae, cyanobacteria, Aphanothece microscopica Nägeli, Chlorella

vulgaris, mixotrophic cultures.

Microalgae are eukaryotic, as the green algae, or prokaryotic photosynthetic microorganisms, as the cyanobacteria. These microorganisms have attracted interest due to ability to remove organic matter and nutrients by incorporation into the biomass, suggesting its application in wastewater treatment. Microalgae are preferentially grown photoautotrophical systems, using solar energy with CO2 fixing. Alternatively, these

microorganisms can be cultivated on heterotrophic or mixotrophic growth, using organic compounds as energy and carbon source, such as organic acids, acetate and sugars. Although glucose is the most commonly used carbon source for heterotrophic and mixotrophic cultures of microalgae, information on the concentration required for optimal metabolic growth is too scattered to reach a definite conclusion. Cyanobacterium

Aphanothece microscopica Nägeli has great application in the valorization of organic

residues in the south of Brazil, being recognized for its potential to remove organic matter from agro-industrial effluents into heterotrophic cultures, i.e. the absence of light. Genus

Chlorella is one of the most studied among the microalgae, due to biomass composition in

terms of protein and lipids. Moreover, this microalga is frequently used to wastewaters treatment. In this context, this work aims to evaluate the effect of different concentrations of glucose in the growth of microalgae Aphanothece microscopica Nägeli and Chlorella

vulgaris in mixotrophic conditions. The experiment were conducted at the Laboratory of

Applied Microbiology (LABMAC/CCA/UFSCar), in Erlenmeyer flasks containing 150 mL of inoculum (10% v/v; 106 cell/mL) in BGN and WC media (for Aphanothece and

Chlorella, respectively), supplemented with different concentrations of glucose (0, 12.5,

25, 37.5 and 50g/L). Experiments were set up at 25ºC, photoperiod of 12 hours (light-dark with photon flux density of 30µmol/m2.s) and air-flow rate of 1VVM. Aphanothece

microscopica Nägeli presented the maximum specific growth rate (µmax) at the

intermediate concentration of glucose, 25g/L (µmax = 0.051 h-1), reflecting a duplication

time (td) of 13.5h. For Chlorella vulgaris, the concentration of 12.5g/L of glucose led to

better growth, with µmax = 0.024 h-1 and td = 28h. For both species, the smallest µmax,

consequently, higher tg, were observed when glucose were not added to the medium.

Although cultures are mixotrophic, both BGN and WC medium shows no organic source, so that the addition of glucose is interesting to keep the metabolism during the dark period. Additionally, the addition of organic substrate results in increases growth rate. The second lowest µmax was observed at higher concentration of glucose (50g/L), which was due,

probably, to the inhibitory effect of the substrate. Preliminary results suggest that the mixotrophic system using an organic substrate constitutes an interesting alternative, since the presence of the substrate could contribute to the maintenance of metabolism in the dark period, in addition to supporting the attainment of high cell concentrations.

HYGIENIC QUALITY OF CHEESE PRODUCED IN SOUTHERN RIO GRANDE