Hi all,
I'm doing some research in the proteins secreted by L rhamnosus and I've been trying to optimise the fermentation conditions to maximise production of these proteins. Without pH control the media pH drops pretty rapidly to around pH 3, and my research has shown that at around pH 4.5 all of the secreted proteins have precipitated. I've therefore been attempting to control the pH to prolong the fermentation times in order to increase the amount of secreted proteins. pH 5.0 and 6.0 seems to yield a similar array of secreted proteins over a 24 h fermentation, whereas pH 7.0 shows a lot more protein in the media, and a very different array of proteins to the lower pHs.
Is this something anyone else has come across, and is there a reason why most research I can find doesn't talk about fermentation of lactobacilli at pH as high as pH 7.0?
Optimal initial pH value for the growth is in the range from 6.4 to 4.5. It grows as rods, single rods or in short chains.
Hi,
Lactobacillus rhamnosus is a Gram-positive, non-sporeforming, facultatively anaerobic or microaerophilic, non-motile and catalase-negative bacterium. It belongs to mesophilic organisms, but in dependence on the strain, its cultures may grow at temperatures lower than 15 °C or higher than 40 °C. To grow, it requires a lot of vitamins including folic acid, riboflavin, niacin, pantothenic acid and mineral calcium [1]. Optimal initial pH value for the growth is in the range from 6.4 to 4.5. It grows as rods, single rods or in short chains. The dimension of the cells is from 0.8 to 1.0 μm in width and from 2.0 to 4.0 μm in length [2]
Optimal initial pH value for the growth is in the range from 6.4 to 4.5. It grows as rods, single rods or in short chains.
Optimal intial pH values for the growth in the range 4.5 - 6.4 it grows as rods, single rods in short chain
Thanks everyone.
As a follow-up, what would the effect be if grown at pH 7.0? And also, as this is a facultative anaerobe would might the effect of growing either with air bubbles through or under anaerobic conditions?
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