Lactobacillus acetotolerans, a New Species from Fermented Vinegar Broth

Abstract

Thirteen strains of rod-shaped lactic acid bacteria, resistant to high concentrations of acetic acid, were isolated from the fermented broth of rice vinegar. These isolates showed homofermentation and differed from all the validly described homofermentative species of the genus Lactobacillus. Although the isolates were divided into two groups on the basis of acid production pattern from carbohydrates and nutritional requirements for growth, all showed extremely high deoxyribonucleic acid homology. The isolates were considered to represent a new species of the genus Lactobacillus. The two groups, based on their biochemical and physiological properties, were treated as biovar I and biovar II. A new species proposed for these isolates was named Lactobacillus acetotolerans. The type strain of L. acetotolerans sp. nov. is NBI 3014 (= JCM 3825).Acetic acid bacteria are usually the only bacteria that can grow in fermenting vinegar broth, which ordinarily contains more than 2 to 3% acetic acid. However, on rare occasions, lactic acid bacteria tolerant to acetic acid grow in the fermenting vinegar broth and cause turbidity in the broth (5). During a study of microorganisms in vinegar production, lactic acid bacteria that showed an unusually high tolerance to acetic acid were isolated from the turbid broth of rice vinegar and were thought to represent a new taxon of lactic acid bacteria.The present study deals with the characterization of these isolates and a description of their taxonomic status. The results indicate that they can be regarded as a new species for which the name Lactobacillus acetotolerans is proposed. MATERIALS AND METHODSBacterial strains. Thirteen strains (Table 1) were isolated from fermented rice vinegar broth which had turned turbid. Nakagawa medium (Asahi Breweries Ltd., Tokyo, Japan), useful for selection of lactic acid bacteria (20), supplemented with 1% agar (5) was used for the isolation of the bacteria. A number of other Lactobacillus species were examined for comparison (Table 1) Cultivation media. Unless otherwise stated, the bacteria were cultivated on Briggs liver broth (pH 5.0) (16) at 30°C. The authentic strains, except for L . homohiochii ATCC 15434*, were cultivated on Briggs liver broth (pH 6.8) at 30°C. For L . homohiochii ATCC 15434*, Briggs liver broth was supplemented with 10 c1. g of DL-mevalonic acid lactone per ml and 7% (voVvol) ethanol (pH 5.0). L . catenaforme JCM 1121T was cultivated anaerobically in a GasPak jar (BBL Microbiology Systems, Cockeysville, Md.). For solid media, 1.5% agar was added to the above liquid media.Morphology of the isolates. Cell shape, cell size, cell arrangement, and Gram stain were observed for cells grown in Briggs liver broth (pH 5.0) after 3 to 5 days at 30°C. The * Corresponding author. cells were also observed with a JEOL scanning electron microscope (model JSM-T20). The modification of Hucker and Conn was used for the Gram stain (8). The motility of the cells cultured on a Briggs agar plate (pH 5.0) (1) was tested after 3 to 21 days at 25 a...

Description of a French natural wheat sourdough over 10 consecutive days focussing on the lactobacilli present in the microbiota

“…acetotolerans are seldom found in wheat sourdoughs. They were isolated for the first time respectively from fermented vinegar broth and beer malt and wort (Entani et al 1986;Bohak et al 1998). Nevertheless, these two species have already been observed in wheat cereal products.…”

“…Moreover, Lb. acetotolerans has been shown to tolerate high concentrations of acetic acid at low pH, up to 5% at pH 3.5 (Entani et al 1986). Considering the overall lactobacilli microbiota, Lb.…”

“…amylolyticus and Lb. acetotolerans, possess a strong ability to decrease the pH and have been reported to grow at low pH, respectively 3.5 and 3.3 (Entani et al 1986;Bohak et al 1998). Moreover, Lb.…”

Monitoring the bacterial community of maize silage stored in a bunker silo inoculated with Enterococcus faecium, Lactobacillus plantarum and Lactobacillus buchneri

“…Lact. acetotolerans is a homofermentative, facultative anaerobic bacterium and is resistant to acetic acid at a concentration of 40–50 g l −1 at pH 3·5 (Entani et al. 1986).…”

Lactobacillus pasteurii sp. nov. and Lactobacillus hominis sp. nov.

“…The growing Lactobacillus acidophilus/Lactobacillus delbrueckii complex includes species isolated from different environments such as the intestine of weaning piglets (Konstantinov et al, 2006), a racehorse (Morita et al, 2010), mice, rats or hamsters (Mitsuoka & Fujisawa 1987;Fujisawa et al, 1990), chicken intestine or crop (Mukai et al, 2003;Fujisawa et al, 1992;Cousin et al, 2012) and different parts of the human body (Brygoo & Aladame, 1953;Hansen & Mocquot, 1970;Roos et al, 2005;Fujisawa et al, 1992;Lauer & Kandler, 1980;Falsen et al, 1999), as well as dairy products (Rogosa & Hansen, 1971;Dellaglio et al, 2005;Weiss et al, 1983) and distilled or fermented products (Howey et al, 1990;Nakamura 1981;Vancanneyt et al, 2004;Bohak et al, 1998;Orla-Jensen, 1919;Nakamura & Crowell, 1979;Entani et al, 1986;Wang et al, 2009). Strain 61D T was isolated from intestine of human origin (Gasser, 1970;Gasser & Sebald, 1966), while strain 1517 T was of unknown origin according to the archives of F. Gasser.…”