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PubMed2004

Biofilm formation by Stenotrophomonas maltophilia: modulation by quinolones, trimethoprim-sulfamethoxazole, and ceftazidime.

We investigated the in vitro effects of seven fluoroquinolones (ciprofloxacin, grepafloxacin, levofloxacin, moxifloxacin, norfloxacin, ofloxacin, and rufloxacin), compared to those of trimethoprim-sulfamethoxazole (SXT) and ceftazidime on total biomass and cell viability of Stenotrophomonas maltophilia biofilm. S. maltophilia attached rapidly to polystyrene, within 2 h of incubation, and then biofilm formation increased over time, reaching maximum growth at 24 h. In the presence of fluoroquinolones at one-half and one-fourth the MIC, biofilm biomass was significantly (P < 0.01) reduced to 55 to 70% and 66 to 76% of original mass, respectively. Ceftazidime and SXT did not exert any activity. Biofilm bacterial viability was significantly reduced by all antibiotics tested at one-half the MIC. At one-fourth the MIC all antibiotics, except levofloxacin, significantly reduced viability. Treatment of preformed biofilms with bactericidal concentrations (500, 100, and 50 micro g/ml) of all fluoroquinolones caused, except for norfloxacin, significant reduction of biofilm biomass to 29.5 to 78.8, 64.1 to 83.6, and 70.5 to 82.8% of original mass, respectively. SXT exerted significant activity at 500 micro g/ml only. Ceftazidime was completely inactive. Rufloxacin exhibited the highest activity on preformed biofilm viability, significantly decreasing viable counts by 0.6, 5.4, and 17.1% at 500, 100, and 50 micro g/ml, respectively. Our results show that (i) subinhibitory (one-half and one-fourth the MIC) concentrations of fluoroquinolones inhibit adherence of S. maltophilia to polystyrene and (ii) clinically achievable concentrations (50 and 100 micro g/ml) of rufloxacin are able to eradicate preformed S. maltophilia biofilm.

Anti-Infective Agents↗

PubMed1972

Effects of acridine orange on the growth of Escherichia coli.

Exposure of Escherichia coli to critical acridine orange (AO) concentrations did not result in loss of viability. However, the deoxyribonucleic acid (DNA) of cells exposed to such agents was rapidly degraded and repolymerized. On the other hand, a bacterium deficient in DNA repair (pol A(1) (-), lacking DNA polymerase) was sensitive to the action of AO. The DNA of such cells was also degraded but it was not repaired.

Acridines↗

PubMed1995

Suppression of thermosensitive initiation of DNA replication in a dnaR mutant of Escherichia coli by a rifampin resistance mutation in the rpoB gene.

The thermosensitivity of the Escherichia coli dnaR130 mutant in initiation of DNA replication was suppressed by a spontaneous rifampin resistance mutation in rpoB, the gene for the beta subunit of RNA polymerase. Among the dnaR-suppressing rpoB alleles obtained was rpoB22, which was able to suppress the thermosensitivity of the dnaA46 or dnaA167 mutant, but not that of the dnaA5 mutant, in initiation of replication. Some dnaA-suppressing rpoB alleles obtained from rifampin-resistant derivatives of the dnaA mutants were able to suppress the dnaR defect. The dnaR mutant with the rpoB22 allele was deprived of thermoresistance by the dnaA5 mutation and of viability at low and high temperatures by the dnaA46 but not the dnaA167 mutation. The results show that the rpoB-mediated suppression of the dnaA or dnaR defect depends on the functions of both dnaA and dnaR products. I propose that the dnaR product has a key role in transcriptional activation of the replication origin for the dnaA-dependent initiation of DNA replication.

Alleles↗

PubMed2000

Flavodoxin mutants of Escherichia coli K-12.

The flavodoxins are flavin mononucleotide-containing electron transferases. Flavodoxin I has been presumed to be the only flavodoxin of Escherichia coli, and its gene, fldA, is known to belong to the soxRS (superoxide response) oxidative stress regulon. An insertion mutation of fldA was constructed and was lethal under both aerobic and anaerobic conditions; only cells that also had an intact (fldA(+)) allele could carry it. A second flavodoxin, flavodoxin II, was postulated, based on the sequence of its gene, fldB. Unlike the fldA mutant, an fldB insertion mutant is a viable prototroph in the presence or absence of oxygen. A high-copy-number fldB(+) plasmid did not complement the fldA mutation. Therefore, there must be a vital function for which FldB cannot substitute for flavodoxin I. An fldB-lacZ fusion was not induced by H(2)O(2) and is therefore not a member of the oxyR regulon. However, it displayed a soxS-dependent induction by paraquat (methyl viologen), and the fldB gene is preceded by two overlapping regions that resemble known soxS binding sites. The fldB insertion mutant did not have an increased sensitivity to the effects of paraquat on either cellular viability or the expression of a soxS-lacZ fusion. Therefore, fldB is a new member of the soxRS (superoxide response) regulon, a group of genes that is induced primarily by univalent oxidants and redox cycling compounds. However, the reactions in which flavodoxin II participates and its role during oxidative stress are unknown.

Bacterial Proteins↗

PubMed2002

The PrpC serine-threonine phosphatase and PrkC kinase have opposing physiological roles in stationary-phase Bacillus subtilis cells.

Loss of the PrpC serine-threonine phosphatase and the associated PrkC kinase of Bacillus subtilis were shown to have opposite effects on stationary-phase physiology by differentially affecting cell density, cell viability, and accumulation of beta-galactosidase from a general stress reporter fusion. These pleiotropic effects suggest that PrpC and PrkC have important regulatory roles in stationary-phase cells. Elongation factor G (EF-G) was identified as one possible target of the PrpC and PrkC pair in vivo, and purified PrpC and PrkC manifested the predicted phosphatase and kinase activities against EF-G in vitro.

Bacillus subtilis↗

PubMed1978

Sensitivity of urine-grown cells of Providencia stuartii to antiseptics.

Urine-grown cultures of 23 clinical isolates of Gram-negative bacteria having a range of minimum inhibitory concentration values for chorhexidine were challenged with various concentrations of this antiseptic. The results suggest that cells of Providencia stuartii, in particular, exhibit a considerable degree of resistance to chlorhexidine under these conditions, concentrations of up to 10 000--20 000 microgram/ml of urine being necessary to produce complete loss of viability of such cultures. Of the other two antiseptics tested, phenoxyethanol proved to be the more effective, the recommended use concentration of 2% v/v producing reductions in viable counts of greater than six logarithms in all the strains examined. It is suggested that phenoxyethanol may be a suitable alternative to the cationic agents for use in antiseptic policies for bladder management of urinary tract infections with Providencia stuartii.

Anti-Infective Agents, Local↗

PubMed1999

An allele of the yeast RPB7 gene, encoding an essential subunit of RNA polymerase II, reduces cellular resistance to the antitumor drug bleomycin.

Bleomycin is an antitumor drug that kills cells by introducing lesions in DNA. Thus, normal cells exposed to bleomycin must rely on efficient DNA repair mechanisms to survive. In the yeast Saccharomyces cerevisiae, the transcriptional activator Imp2 is required to fend off the toxic effects of bleomycin. However, it remains unclear whether Imp2 controls the expression of a protein that either repairs bleomycin-induced DNA lesions, or detoxifies the drug, and or both. To gain further insight into the mechanisms by which yeast cells mount a response towards bleomycin, we began to sequentially characterize the genetic defect in a collection of bleomycin-sensitive mutants that were previously isolated by mini-Tn3 transposon mutagenesis. A rescue plasmid designed to integrate at the site of the mini-Tn3 insertion was used to identify the defective gene in one of the mutant strains, HCY53, which was not allelic to IMP2. We showed that in strain HCY53, the mini-Tn3 was inserted at the distal end of an essential gene RPB7, which encodes one of the two subunits, Rpb4-Rbp7, that forms a subcomplex with RNA polymerase II. Since rpb7 null mutants are nonviable, it would appear that the rpb7::mini-Tn3 allele produces a protein that retains partial biological function thus permitting cell viability, but which is unable to provide bleomycin resistance to strain HCY53. The defective phenotype of strain HCY53 could be corrected by a plasmid bearing the entire RPB7 gene. Two dimensional gel analysis revealed that the expression of several proteins were diminished or absent in the rpb7::mini-Tn3 mutant when challenged with bleomycin. These results are in accord with our previous report that bleomycin resistance in yeast is controlled at the transcriptional level.

Alleles↗

PubMed2005

Induction of heat shock protein 72 in C6 glioma cells by methyl jasmonate through ROS-dependent heat shock factor 1 activation.

Salicylate and jasmonates are two different types of plant hormone that play critical roles in plant defense responses against insect herbivores and microbial pathogens, through activating defense genes. These two natural products have been shown to have similar activities in animal cells: the compounds are able to induce cell cycle arrest or apoptosis in a variety of human cancer cells including those of colon, prostate, breast, and leukemia, suggesting the chemicals may potentially be a novel class of anti-cancer drugs. Since sodium salicylate can induce the heat shock response in animals, we examined the effects of jasmonates on the heat shock response in C6 glioma cells. Here, we show that brief exposure to methyl jasmonate (MeJA), but not to jasmonic acid, induces heat shock protein 72 (HSP72), but not HSP73 and HSP90, via heat shock factor I (HSF1) activation in C6 glioma cells without affecting cell viability. Intracellular H2O2 and O2-, and mitochondrial ROS were prominently increased in response to 5 mM MeJA in C6 cells. MeJA-induced HSP72 expression, HSF1 DNA binding, and human HSP70 promoter-driven CAT activity were prevented by N-acetyl-L-cysteine (a general antioxidant), catalase (a specific antioxidant for H2O2), and sodium formate (an inhibitor of OH.), but not by Rac1 dominant negative mutant Rac1N17 and diphenyleneiodonium (a NADPH oxidase inhibitor), indicating that MeJA induces HSP72 expression though HSF1 that is activated via Rac1-NADPH oxidase-independent ROS production pathway. These results suggest that the plant stress hormones share the ability to induce heat shock response in animal cells.

Acetates↗

PubMed1975

[Sensitivity of pathogenic clostridia to antibiotics].

By the sensitivity levels of the gas infection causative agents, i. e. pathogenic Clostridia to antibiotics, the latter were conditionally divided into 4 groups. The 1st group included the most active antibiotics, such as tetracyclines,, penicillins, cephalosporins, rifampicin, 7-chlor-7-desoxylincomycin. Their minimum inhibitory and bactericidal concentrations did not usually exceed 2 gamma/ml. For most of the strains the inhibitory and bactericidal concentrations amounted to the tenth and hundredth fractions of gamma/ml. The antibiotics of the 2nd group, i. e. erythromycin, lincomycin,ristomycin and levomycetin inhibited multiplication and viability of pathogenic Clostridia in concentrations of 20 gamma/ml. Erythromycin was most active among them The 3rd group consisted of oleandomycin, novobiocin, geliomycin and azalomycin, the minimum inhibitory concentrations of them being 20 to 50 gamma/ml. The antibiotics of the 4th group, i. e. neomycin, monomycin, kanamycin, streptomycin, polymyxin and others affected pathogenic Clostridia at very high concentrations, amounting to the hundrenth and thousandth of gamma/ml.

Anti-Bacterial Agents↗

PubMed1997

Vitamin C inhibits the growth of a bacterial risk factor for gastric carcinoma: Helicobacter pylori.

BACKGROUND: Helicobacter pylori infection is a risk factor for gastric carcinogenesis. High dietary vitamin C intake appears to protect against gastric carcinoma. It has been suggested that vitamin C exerts the protective effect by scavenging free radicals that may be enhanced by H. pylori. However, vitamin C has not been investigated in relation to the direct action on H. pylori. In this study, the authors attempted to clarify this possibility both in vitro and in vivo. METHODS: Susceptibility testing of H. pylori (64 strains) was performed by the agar dilution method. Bactericidal actions were determined by a broth cultivation technique. The effect of vitamin C on in vivo H. pylori colonization was evaluated by using the Mongolian gerbil model. RESULTS: At concentrations of 2048, 512, and 128 microg/mL (minimum inhibitory concentrations [MICs]), vitamin C could inhibit the growth of 90% of the bacterial stains incubated at pH values of 7.4, 6.0, and 5.5, respectively. The broth cultures exposed to the MICs of vitamin C displayed a 1.57 approximately 2.5-log decrease in the number of viable bacteria, and the loss of viability was observed in 24 hours at concentrations 8-fold higher than the MICs. In an in vivo experiment, H. pylori colonies decreased significantly in animals treated with vitamin C after oral administration of vitamin C (10 mg/head/day) for 7 days. CONCLUSIONS: High doses of vitamin C inhibit the growth of H. pylori in vitro as well as in vivo.

Animals↗

PubMed2001

[Operating Procedure of Collection, Processing and Preservation of 3000 Units Umbilical Cord Blood in Shangdong Cord Blood Bank]

The experience with the umbilical cord blood (UCB) stem cells for unrelated transplantation from our 3 000 UCB storage was described. UCB, collected from closed blood bags, were mixed with hydroxyethyl starch for nucleated cell (NC) enrichment. After finishing CD34 analysis, culture of hematopoietic progenitors (CFU-GM and CFU-GEMM) assays, microbial culture, HLA Class I (A, B) serology and class II (DR) low resolution SSP typing, cord blood units are stored in the liquid nitrogen for clinical applicatoin. Cord blood contained an average of nuclear cell (NC) (1.2 +/- 0.6) x 10(9), CD34(+) cells (3.0 +/- 3.7) x 10(6), CFU-GM (1.1 +/- 0.7) x 10(6) and CFU-GEMM (1.1 +/- 1.2) x 10(6) for storage and the recovery rates were 91%, 88%, 85% and 82%, respectively. The recovery rates for red blood cell and Hb were (39 +/- 9)% and (40 +/- 8)%, respectively. The storage volume was (35.1 +/- 7.1) ml in a 50 ml storage bags. The mean time from collection to processing of 15 hours (range 4 - 24 hours) had no influence on cell viability. The cell viability before processing is more than 95% and 92% after UCB thawing. The recovery rates of NC, CD34(+) cells and CFU-GM post-thawing were 96%, 90% and 91%, respectively. There were no HIV antibody (HIVAb) positive in all of UCB units. For an incidence of processed samples, infection with syphilis, HBsAg, HBcAb, HCVAb, CMV, bacterial contamination and abnormal hemoglobin were 0.1%, 0.8%, 3.2%, 0.2%, 87.1%, 1.2% and 0.1%, respectively. More than 3 HLA loci matched can be found for random patients in our cord blood bank and 6 HLA loci matched have 5%. For transplantation with nucleated cell counts of > 2.7 x 10(7) cells/kg, our cord blood bank will be able to provide all of the umbilical cord blood stem cell samples for children and 50% of units can be used for some of adult recipients transplantation in the country. It is concluded that: (1) The large cord blood banking for 20 000 UCB storage is feasible in China. (2) Our system of whole procedure and methods is functionable for supplying qualified cord blood units in transplantation. (3) The volume for collection is critical to the yield of CD34(+) cells or hematopoietic progenitor cells, however cord blood NC is also important and proportional with CD34(+) cells. Only the units containing more than 8 x 10(8) cells and more than 60 ml of cord blood can be in the procession for storage.

Journal Article↗

PubMed2001

Antimicrobial properties of garlic oil against human enteric bacteria: evaluation of methodologies and comparisons with garlic oil sulfides and garlic powder.

The antimicrobial effects of aqueous garlic extracts are well established but those of garlic oil (GO) are little known. Methodologies for estimating the antimicrobial activity of GO were assessed and GO, GO sulfide constituents, and garlic powder (GP) were compared in tests against human enteric bacteria. Test methodologies were identified as capable of producing underestimates of GO activity. Antimicrobial activity was greater in media lacking tryptone or cysteine, suggesting that, as for allicin, GO effects may involve sulfhydryl reactivity. All bacteria tested, which included both gram-negative and -positive bacteria and pathogenic forms, were susceptible to garlic materials. On a weight-of-product basis, 24 h MICs for GO (0.02 to 5.5 mg/ml, 62 enteric isolates) and dimethyl trisulfide (0.02 to 0.31 mg/ml, 6 enteric isolates) were lower than those for a mixture of diallyl sulfides (0.63 to 25 mg/ml, 6 enteric isolates) and for GP, which also exhibited a smaller MIC range (6.25 to 12.5 mg/ml, 29 enteric isolates). Viability time studies of GO and GP against Enterobacter aerogenes showed time- and dose-dependent effects. Based upon its thiosulfinate content, GP was more active than GO against most bacteria, although some properties of GO are identified as offering greater therapeutic potential. Further exploration of the potential of GP and GO in enteric disease control appears warranted.

Allyl Compounds↗

PubMed1991

[The action of helium-neon laser radiation on the growth of Mycobacterium tuberculosis].

The growth properties of M. tuberculosis subjected to the action of helium-neon laser radiation was studied. Laser radiation was shown to change the quantitative and qualitative composition of mycobacterial population. Disturbances in the viability of mycobacteria appear as a consequence of changes in the morphological structure of mycobacterial cells. The maximum effect of helium-neon laser radiation was achieved after the irradiation of M. tuberculosis culture on days 2-3 after inoculation. These results made it possible to suggest that the effect of helium-neon laser radiation was most pronounced in cells at the stage of mitosis (the logarithmic stage of growth) with the highest degree of metabolism.

Colony Count, Microbial↗

PubMed2001

The growth and interaction of yeasts and lactic acid bacteria isolated from Zimbabwean naturally fermented milk in UHT milk.

Nine yeast and four lactic acid bacterial strains, previously isolated from Zimbabwean traditionally fermented milk, were inoculated into ultra-high temperature treated (UHT) milk in both single and yeast-lactic acid bacteria co-culture. The lactic acid bacteria (LAB) strains consisted of Lactococcus lactis subsp. lactis biovar. diacetylactis C1, L. lactis subsp. lactis Lc39, L. lactis subsp. lactis Lc261 and Lactobacillus paracasei subsp. paracasei Lb11. The yeast strains used were Candida kefyr 23, C. lipolytica 57, C. lusitaniae 63, C. lusitaniae 68, C. tropicalis 78, Saccharomyces cerevisiae 71, S. dairenensis 32, C. colliculosa 41 and Dekkera bruxellensis 43. After 48-h fermentation at 25 degrees C, the samples were analysed for pH, viable yeast and bacterial counts, organic acids, volatile organic compounds (VOC) and carbon dioxide. The Lactococcus strains reduced the pH from about 6.6 to between 4.0 and 4.2, while Lb. paracasei subsp. paracasei Lb11 reduced the pH to about 5.4. Most of the yeasts, however, did not affect the final pH of the milk except for C. kefyr 23, which reduced the pH from 6.6 to 5.8. All the Lactococcus strains grew two log cycles during the 48-h fermentation period, while Lb. paracasei subsp. paracasei Lb11 grew about one log cycle. S. cerevisiae 71, C. colliculosa 41 and D. bruxellensis 43 showed poor growth in the milk in both single and co-culture. The other species of yeast grew about two log cycles. Candida colliculosa 41, S. dairenensis 32 and D. bruxellensis 43 showed reduced viability when in co-culture with Lb. paracasei subsp. paracasei Lb11. The samples in which C. kefyr 23 was used were distinct and characterised by large amounts of acetaldehyde, carbon dioxide and ethanol. However, in the samples where S. dairenensis, C. colliculosa, D. bruxellensis, C. lusitaniae, C. tropicalis, C. lipolytica and S. cerevisiae were used in co-culture, the final pH and metabolite content were mainly determined by the correspondin

Animals↗

PubMedDate not supplied

Fungicidal effect of tyrothricin on Candida albicans.

Tyrothricin, a polypeptide antibiotic, is active against yeast cells. Tyrothricin was rapidly fungicidal towards Candida albicans. Concentration of four times the minimum inhibitory (25 mg l-1) reduced the yeast numbers by more than 3 log10 within 1 h. Similar results were obtained in a flow cytometric antifungal activity assay using the new two-colour probe for yeast viability, FUN-1, which measures impairment of metabolic activity. The respiratory activity of Candida albicans, measured in a XTT kinetic assay, was significantly reduced in comparison with controls by 3.12 mg l-1 of the substance. Because fungicidal concentrations of tyrothricin are locally achievable in patients, an evaluation of the local effect of tyrothricin in patients suffering from mucosal infections with Candida species should be considered.

Antifungal Agents↗

PubMed2001

Green fluorescent protein as a novel indicator of antimicrobial susceptibility in Aureobasidium pullulans.

Presently there is no method available that allows noninvasive and real-time monitoring of fungal susceptibility to antimicrobial compounds. The green fluorescent protein (GFP) of the jellyfish Aequoria victoria was tested as a potential reporter molecule for this purpose. Aureobasidium pullulans was transformed to express cytosolic GFP using the vector pTEFEGFP (A. J. Vanden Wymelenberg, D. Cullen, R. N. Spear, B. Schoenike, and J. H. Andrews, BioTechniques 23:686-690, 1997). The transformed strain Ap1 gfp showed bright fluorescence that was amenable to quantification using fluorescence spectrophotometry. Fluorescence levels in Ap1 gfp blastospore suspensions were directly proportional to the number of viable cells determined by CFU plate counts (r(2) > 0.99). The relationship between cell viability and GFP fluorescence was investigated by adding a range of concentrations of each of the biocides sodium hypochlorite and 2-n-octylisothiozolin-3-one (OIT) to suspensions of Ap1 gfp blastospores (pH 5 buffer). These biocides each caused a rapid (< 25-min) loss of fluorescence of greater than 90% when used at concentrations of 150 microg of available chlorine ml(-1) and 500 microg ml(-1), respectively. Further, loss of GFP fluorescence from A. pullulans cells was highly correlated with a decrease in the number of viable cells (r(2) > 0.92). Losses of GFP fluorescence and cell viability were highly dependent on external pH; maximum losses of fluorescence and viability occurred at pH 4, while reduction of GFP fluorescence was absent at pH 8.0 and was associated with a lower reduction in viability. When A. pullulans was attached to the surface of plasticized poly(vinylchloride) containing 500 ppm of OIT, fluorescence decreased more slowly than in cell suspensions, with > 95% loss of fluorescence after 27 h. This technique should have broad applications in testing the susceptibility of A. pullulans and other fungal species to antimicrobial compounds.

Ascomycota↗

PubMed2006

[Inactivation of mycobacteria by disinfectants with a tuberculocidal label].

INTRODUCTION: Disinfectants available in Venezuela, registered as tuberculocidal, and used in clinical and laboratory settings were tested for their mycobactericidal activity. METHODS: The European Standard Quantitative Suspension test prEN14348 was used in simulated clean and dirty conditions. The disinfectants tested included Gerdex and K-ller (both containing the quaternary ammonium compound dimethyl benzyl lauryl ammonium bromide in concentrations of 10% and 0.16% respectively), Microplus-Action (5% polymethylene urea), Cidex (2% glutaraldehyde) and Cidex OPA (0.55% ortho-phthalaldehyde). The mycobactericidal activity was evaluated with M. smegmatis ATCC 19420 and in clinical isolates of M. fortuitum, M. chelonae and M. abscessus. The tuberculocidal activity was assessed with M. tuberculosis H37Rv. RESULTS: Cidex and Cidex OPA were effective against all the test organisms, showing a > 5-log 10 reduction in CFU after 5 minutes of exposure under both clean and dirty conditions. Gerdex and K-ller only achieved a 2-log reduction in M. tuberculosis, M. abscessus and M. chelonae CFU, even after 60 minutes of exposure. Micro Plus Action showed a 4-log reduction in M. tuberculosis viability but less than a 1-log reduction in M. abscessus and M. chelonae CFUs after 60 minutes of incubation. CONCLUSION: The tuberculocidal activity claimed by the manufacturers of several disinfectants sold in Venezuela, Gerdex, K-ller and Microplus-Action is inaccurate when tested by European norms. The use of these products for disinfecting material used in critical and semi-critical patients could result in iatrogenic infections.

Antitubercular Agents↗

PubMed2006

Applicability of pectate-entrapped Lactobacillus casei cells for L(+) lactic acid production from whey.

Lactic acid is a versatile organic acid, which finds major application in the food, pharmaceuticals, and chemical industries. Microbial fermentation has the advantage that by choosing a strain of lactic acid bacteria producing only one of the isomers, an optically pure product can be obtained. The production of L: (+) lactic acid is of significant importance from nutritional viewpoint and finds greater use in food industry. In view of economic significance of immobilization technology over the free-cell system, immobilized preparation of Lactobacillus casei was employed in the present investigation to produce L: (+) lactic acid from whey medium. The process conditions for the immobilization of this bacterium using calcium pectate gel were optimized, and the developed cell system was found stable during whey fermentation to lactic acid. A high lactose conversion (94.37%) to lactic acid (32.95 g/l) was achieved with the developed immobilized system. The long-term viability of the pectate-entrapped bacterial cells was tested by reusing the immobilized bacterial biomass, and the entrapped bacterial cells showed no decrease in lactose conversion to lactic acid up to 16 batches, which proved its high stability and potential for commercial application.

Biotechnology↗