Riccardo Scotti

THE EFFECT OF COMPOST AND SEWAGE SLUDGE ON SOIL BIOLOGIC ACTIVITIES IN SALT AFFECTED SOIL

Saline soil was amended with 13.3 and 26.6 g kg -1 of Municipal Solid Waste (MSW) compost or sewage sludge, and arylsulphatase (ARY), phosphatase (PHO), dehydrogenase (DEH), β-glucosidase (β-GLU), urease (URE) and catalase (CAT) activities as well as physical-chemical properties were determined after 70 day of incubation under laboratory conditions. MSW compost and sewage sludge significantly improved soil physical-chemical properties, especially carbon and nitrogen contents. Accordingly, overall enzyme activities were substantially promoted in presence of both amendments and the higher increases were measured at 13.3 g kg -1 of MSW compost (increases by 107%, 43%, 20%, 11%, and 148% for, DEH, β-GLU, PHO, URE, and CAT, respectively). Lower beneficial effects occurred at 26.6 g kg -1 of sewage sludge possibly because of the increased salinity or the presence of trace elements by sewage sludge application. As a general response, MSW compost supplied at 13.3 g kg -1 seems

Vertical and horizontal distributions of microbial abundances and enzymatic activities in propylene-glycol-affected soils

The natural microbial activity in the unsaturated soil is vital for protecting groundwater in areas where high loads of biodegradable contaminants are supplied to the surface, which usually is the case for airports using aircraft de-icing fluids (ADF) in the cold season. Horizontal and vertical distributions of microbial abundance were assessed along the western runway of Oslo Airport (Gardermoen, Norway) to monitor the effect of ADF dispersion with special reference to the component with the highest chemical oxygen demand (COD), propylene glycol (PG). Microbial abundance was evaluated by several biondicators: colony-forming units (CFU) of some physiological groups (aerobic and anaerobic heterotrophs and microscopic fungi), most probable numbers (MPN) of PG degraders, selected catabolic enzymatic activities (fluorescein diacetate (FDA) hydrolase, dehydrogenase, and β-glucosidase). High correlations were found between the enzymatic activities and microbial counts in vertical soil profiles. All microbial abundance indicators showed a steep drop in the first meter of soil depth. The vertical distribution of microbial abundance can be correlated by a decreasing exponential function of depth. The horizontal trend of microbial abundance (evaluated as total aerobic CFU, MPN of PG-degraders, and FDA hydrolase activity) assessed in the surface soil at an increasing distance from the runway is correlated negatively with the PG and COD loads, suggesting the relevance of other chemicals in the modulation of microbial growth. The possible role of potassium formate, component of runway de-icers, has been tested in the laboratory by using mixed cultures of Pseudomonas spp., obtained by enrichment with a selective PG medium from soil samples taken at the most contaminated area near the runway. The inhibitory effect of formate on the growth of PG degraders is proven by the reduction of biomass yield on PG in the presence of formate.

Draft Genome Sequence of the Plant Growth-Promoting Rhizobacterium Pseudomonas fluorescens Strain CREA-C16 Isolated from Pea (Pisum sativum L.) Rhizosphere.

ABSTRACT Herein, we report the draft genome sequence of Pseudomonas fluorescens strain CREA-C16, a plant growth-promoting rhizobacterium that was isolated from the rhizosphere of Pisum sativum L. plants. The genome sequence is ~6 Mb in size, with a G+C content of 60.1%, and includes 4,457 candidate protein-encoding genes.