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Selection of local
extremophile lactic acid bacteria with high capacity to
degrade lactose: Potential use to reduce intolerance to
lactose in vitro
Koïche, M.* and Dilmi Bouras, A.**
Laboratoire de Bioressources naturelles locales, Faculté des
sciences agronomiques et des sciences biologiques,
universite Hassiba Benbouali de Chlef .BP. 151, Chlef
(02000) – Algerie.
*Corresponding authors. E-mail:
koiche_malika@yahoo.fr. E-mail:
dilmibourasa@hotmail.com. Tel/ fax: 00 (213) 27 72 10
65.
Accepted
19 February, 2010 |
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This
study is related to the isolation and identification of
strains of local thermophilic lactic acid bacteria belonging
to the species, Streptococcus thermophilus and
Lactobacillus bulgaricus. These bacteria can
exist under extreme conditions of the digestive tract
(acidity and high concentration of bile salts) and have a
high capacity to degrade lactose. The aim is to produce
yoguort with the bacteria that remain viable and active in
the digestive tract, so as to enhance lactase activity at
the intolerant lactose. The results also show considerable
variations between genera, species and strains of the same
species in the decomposition of lactose in pure and mixed
cultures (Sc.t5 and Sc.t3,
respectively, with 48 and 42%) (YSLB2, YSLB4
and YSLB1, respectively, with
90.44, 87.22 and 84.28%) of initial lactose after 6 h of
incubation at 37°C while keeping a level of viability higher
than 107 cells/ ml. In the presence of pH (2.5,
4.5 and 6.5), put with or without 0.3% of bile salts, the
results are also unmatched. The best cultures will be used
to manufacture fermented milks (yoghurts) in order to
correct intolerance with lactose in man after having to test
them, in a second part, in vivo.
Key
words:
Lactic acid bacteria, extremophile, intolerance of lactose,
digestive tract. |
