Evaluation of the ability to metabolize 1, 2-propanediol by heterofermentative bacteria of the genus Lactobacillus

Background: New directions of research on lactic acid bacteria include investigation of metabolic pathways for the synthesis and/or metabolism of 1,2-propanediol, commonly used in the food and chemical industry, medicine, pharmacy and cosmetology as well as agriculture. The objective of this study was to compare the capacity of strains representing three diverse heterofermentative species belonging to the genus Lactobacillus to synthesize and/or transform 1,2-PD as well as to suggest new directions of research aimed at commercial use of this metabolite. Results: The novel strain of Lactobacillus buchneri A KKP 2047p, characterized as exhibiting an unusual trait for that species in the form of capacity to metabolize 1,2-PD, grew poorly in a medium containing 1,2-PD as a sole carbon source. The supplementation with glucose facilitated rapid growth of bacteria and use of 1,2-PD for the synthesis of propionic acid. A similar observation was noted for Lactobacillus reuteri. On the other hand, Lactobacillus diolivorans effectively metabolized 1,2-PD which was the sole carbon source in the medium, and the addition of glucose inhibited the synthesis of propionic acid. The experiments also investigated the effect of cobalamin as a diol dehydratase coenzyme involved in the propionic acid synthesis from 1,2-PD whose addition promoted the yield of the reaction in the case of all tested strains. Conclusions: All tested isolates showed the ability to effectively metabolize 1,2-PD (in the presence of cobalamin) and its conversion to propionic acid, which reveals that investigated bacteria meet the essential requirements of microorganisms with a potential application.

Perfil eletroforético do colostro de ovelhas suplementadas com propileno glicol e cobalto associado à vitamina B12 no final da gestação / Electrophoretic profile of the colostrum of ewes supplemented with propylene glycol and cobalt associated with vitamin B12 in late pregnancy

Este trabalho teve por objetivo avaliar o proteinograma do colostro de ovelhas submetidas a administração de propileno glicol e de cobalto associado à vitamina B12 no final da gestação. Dezoito ovelhas da raça Santa Inês, prenhas e com idade variando entre 18 meses a cinco anos foram distribuídas, por amostragem probabilística em três grupos experimentais, aproximadamente 30 dias antes da data prevista para o parto. No Grupo 1 (G1/n=6) foram administrados 30mL de propileno glicol P.A. via oral diariamente; no Grupo 2 (G2/n=6) foi administrado 1mg de cloreto de cobalto em solução a 1% via oral diariamente e 2mg de vitamina B12, via intramuscular semanalmente e no Grupo 3 (G3/n=6): grupo controle. Logo após o parto procedeu-se a colheita de 30mL de colostro, que foram acondicionados em recipientes apropriados e encaminhados ao laboratório. Após homogeneização, adicionou-se a cada 1.000µL de colostro, 75µL de solução de renina, que foi mantido em banho-maria a 37ºC por aproximadamente 20 minutos e centrifugado a 21.000G durante dez minutos em centrífuga refrigerada. Posteriormente, a fração intermediária, correspondente ao soro do colostro, foi aliquotada e mantida em ultrafreezer a -80oC para posterior determinação das proteínas. A determinação da proteína total do soro colostral foi realizada empregando-se reagente comercial. A separação das proteínas foi realizada utilizando-se a técnica de eletroforese em gel de poliacrilamida contendo dodecil sulfato de sódio (SDS-PAGE). Foram identificadas as proteínas IgA, lactoferrina, albumina, IgG de cadeia pesada (IgGCP), ß-caseína, IgG de cadeia leve (IgGCL), ß-lactoglobulina and α-lactoalbumina, não havendo influência da administração dos suplementos na fase final da gestação sobre as concentrações protéicas do colostro.(AU)

This study aimed to evaluate the proteinogram of the colostrum of ewes submitted to administration of propylene glycol and cobalt associated with vitamin B12 in late pregnancy. Eighteen pregnant Santa Inês ewes 18 months to 5 years old were distributed by probabilistic sampling into three experimental groups, about 30 days before the expected delivery date. In group 1 (G1/n=6), daily oral doses of 30ml propylene glycol PA were administered; Group 2 (G2/n=2) received a daily oral dosage of 1mg cobalt chloride in 1% solution and 2mg of vitamin B12 intramuscularly once a week, and Group 3 (G3/n=6) was the control group. Soon after delivery 30mL of colostrum was harvested from each ewe, which were stored in appropriate containers and sent to the laboratory. After homogenization, we added to each 1000µL of colostrum 75µL solution of rennin, which was kept in a water bath at 37°C for about 20 minutes and centrifuged at 21.000G for 10 minutes in a refrigerated centrifuge. Later, the intermediate fraction, corresponding to colostrum whey, was aliquoted and kept in a -80oC ultrafreezer for subsequent determination of proteins. The determination of the total colostral protein whey was performed using a commercial reagent, observing the linearity test for colostrum. The separation of proteins was performed using the technique of electrophoresis on polyacrylamide gel containing sodium dodecyl sulfate (SDS-PAGE). Lactoferrin, IgA, albumin, IgG heavy chain (IgGCP), ß-casein, IgG light chain (IgGCL), ß-lactoglobulin and α-lactalbumin proteins were identified. There was no influence of the administration of supplements during late pregnancy on the concentration of proteins identified in the colostrum of the ewes.(AU)