Humic fractions of forest, pasture and maize crop soils resulting from microbial activity.

Humic substances result from the degradation of biopolymers of organic residues in the soil due to microbial activity. The objective of this study was to evaluate the influence of three different ecosystems: forest, pasture and maize crop on the formation of soil humic substances relating to their biological and chemical attributes. Microbial biomass carbon (MBC), microbial respiratory activity, nitrification potential, total organic carbon, soluble carbon, humic and fulvic acid fractions and the rate and degree of humification were determined.

Synergistic action of both Aspergillus niger and Burkholderia cepacea in co-culture increases phosphate solubilization in growth medium.

Co-inoculation of the fungus Aspergillus niger and the bacterium Burkholderia cepacia was undertaken to understand the interaction between different species of phosphate-solubilizing microorganisms (PSM). PSM were inoculated in a single or mixed (A. niger-B.

Growth and enzymatic responses of phytopathogenic fungi to glucose in culture media and soil.

The effect of inoculation of Aspergillus flavus , Fusarium verticillioides , and Penicillium sp. in Dystrophic Red Latosol (DRL) and Eutroferric Red Latosol (ERL) soils with or without glucose on the total carbohydrate content and the dehydrogenase and amylase activities was studied. The fungal growth and spore production in culture medium with and without glucose were also evaluated.

Control of amylase production and growth characteristics of Aspergillus ochraceus.

The growth and the extracellular amylase production by Aspergillus ochraceus were studied in a stationary culture medium. Maximum growth rate of this fungus was found after 5 days of incubation at 30 degrees C, but maximum amylase production was obtained after 2 days. The highest amylase production were attained with lactose, maltose, xylose and starch as carbon sources.