Evaluation of a formulation for the conservation of Pseudomona aeruginosa strains

Abstract

Humanity has the historic responsibility to solve one of the most important issues of the present time: the environment preservation. While the conservation of plants and animals has been accepted since long time ago, the need of preserving the microbial diversity has received a proper acknowledgement just recently. LIORAD Laboratories have a collection of microbiological cultures obtained from primary subcultures of reference strains, where Pseudomonas aeruginosa was kept freeze-dried using two variants of lipoprotection: 1. Skimmed milk and 2. Glycerol at 20 %. As currently mixtures of additives are widely used, it was evaluated as main goal of the present work a third formulation alternative: Skimmed milk plus peptone at 5 %, which was selected from previous published studies from other authors. In order to check culture preservation an adequate quality control was implemented, which included verification of purity, viability and stability of other key properties (physiological and biochemical). A statistical treatment were performed, using Minitab, V 14.0, for checking if there were significant difference between used lipoprotection variants. Purity and identity showed no variations for the three alternatives, viability in variant 1 as well as in variant three allowed a good survival during the study, which was not the case by using glycerol at 20 %. Statistical results showed there was no significant difference between these variants for 95 % confidential level. By the end of the study it was haven two variants for preserving such strain for a long period of time, the use of skimmed milk at 20 % and the formulation object of the present study.