EVALUATION OF THE ANTIMICROBIAL EFFECTS OF NEW HETEROCYCLIC BIS-QUATERNARY AMMONIUM COMPOUNDS ON BIOFILMS

Considering the well-known mechanism of adaptable resistance of microorganisms to chemical compounds through biofilms formation and the widespread use of N-heterocyclic quaternary ammonium salts (QAC) as disinfectants, in this study we have evaluate the effect of 8 newly synthesized symmetrical and unsymmetrical diquaternary ammonium salts of 1,2-bis-(4-pyridil)-ethane on bacterial biofilms produced by three different bacterial strains. The effect of the exposure to quaternary ammonium salts on biofilm communities was investigated within biofilms obtained in a conventional testing system, on stainless steel and glass surfaces. Differential plate counts were used to characterize the developed communities and the effects of QAC exposure and the results were correlated with epifluorescence microphotographs. The data obtained revealed a significant reduction of bacterial cells in the biofilms tested with 4-7 log CFU for all the QAC

Characterisation of newly polar psychrotrophic streptomycetes isolates from polar soils with cold adapted bioremediation potential

Novel polar streptomycetes coded 4 Alga, P2C4 and MIUG 12P, isolated from soil and vegetation samples prelevated from East Antarctica, were genetically and biochemically characterized in order to set up the phylogeny and to identify the capability to grow at lower temperature and to generate amylase and protease cold-active. The 16S rRNA gene sequence of isolate coded 4 Alga was 100% identical to sequences of Streptomyces sp. isolates from Norway and from Solomon Islands, which also were the closest relatives of P2C4 (99.53%) and MIUG 12P (99.53%) isolates. The data emphasised the skills of the strains Streptomyces 4 Alga, Streptomyces P2C4 and Streptomyces MIUG 12P to biosynthesis cold-adapted amylases and proteases suitable in bioconversion processes at low temperature. These results are quit valuable, because only few streptomycetes, particularly psychrotolerant ones, have so far been explored for their enzymatic potential in cold conditions

Partial characterization of cold active amylases and proteases of Streptomyces sp. from Antarctica

The aim of this study was to isolate novel enzyme-producing bacteria from vegetation samples from East Antarctica and also to characterize them genetically and biochemically in order to establish their phylogeny. The ability to grow at low temperature and to produce amylases and proteases cold-active was also tested. The results of the 16S rRNA gene sequence analysis showed that the 4 Alga rRNA was 100% identical to the sequences of Streptomyces sp. rRNA from Norway and from the Solomon Islands. The Streptomyces grew well in submerged system at 20ºC, cells multiplication up to stationary phase being drastically increased after 120 h of submerged cultivation. The beta-amylase production reached a maximum peak after seven days, while alpha-amylase and proteases were performing biosynthesis after nine days of submerged cultivation at 20ºC. Newly Streptomyces were able to produce amylase and proteases in a cold environment. The ability to adapt to low temperature of these enzymes could make them valuable ingredients for detergents, the food industry and bioremediation processes which require low temperatures