Enzymes in Bast Fibrous Plant Processing

The program COST Action 847 Textile Quality and Biotechnology (2000–2005) has given an excellent chance to review the possibilities of the research, aiming at development of the industrial application of enzymes for bast fibrous plant degumming and primary processing. The recent advancements in enzymatic processing of bast fibrous plants (flax, hemp, jute, ramie and alike plants) and related textiles are given. The performance of enzymes in degumming, modification of bast fibres, roving, yarn, related fabrics as well as enzymatic bonding of lignocellulosic composites is provided.     

Nematode Genera in Forest Soil Respond Differentially to Elevated CO2

Previous reports suggest that fungivorous nematodes are the only trophic group in forest soils affected by elevated CO₂. However, there can be ambiguity within trophic groups, and we examined data at a genus level to determine whether the conclusion remains similar. Nematodes were extracted from roots and soil of loblolly pine (Pinus taeda) and sweet gum (Liquidambar styraciflua) forests fumigated with either ambient air or CO₂-enriched air. Root length and nematode biomass were estimated using video image analysis. Most common genera included Acrobeloides, Aphelenchoides, Cephalobus, Ditylenchus, Ecphyadorphora, Filenchus, Plectus, Prismatolaimus, and Tylencholaimus. Maturity Index values and diversity increased with elevated CO₂ in loblolly pine but decreased with elevated CO₂ in sweet gum forests. Elevated CO₂ treatment affected the occurrence of more nematode genera in sweet gum than loblolly pine forests. Numbers were similar but size of Xiphinema decreased in elevated CO₂. Abundance, but not biomass, of Aphelenchoides was reduced by elevated CO₂. Treatment effects were apparent at the genus levels that were masked at the trophic level. For example, bacterivores were unaffected by elevated CO₂, but abundance of Cephalobus was affected by CO₂ treatment in both forests.     

Characterization of novel phospholipase C from Bacillus licheniformis MTCC 7445 and its application in degumming of vegetable oils

A novel microbial phospholipase C (PLC) from Bacillus licheniformis MTCC 7445 was purified to homogeneity by ammonium sulphate fractionation, dialysis, anion exchange chromatography and gel exclusion chromatography. The bacteria growing on vegetable oils secreted significantly high amount of PLC. The enzyme was purified to 23.4-fold with 46% recovery and specific activity 398 U/mg. It exhibited optimum activity at 70°C and pH 10.0. Using diphosphatidylglycerol as substrate the PLC of B. licheniformis MTCC 7445 had a V _max and K _m of 0.68 mM/min and 32 mM, respectively. It hydrolyzed phosphatidylinositol and phosphatidylserine as well as phosphatidylcholine but not other glycerophospholipids. Its activity was enhanced by 113% with Mn²⁺ and 110% with Mg²⁺. During degumming of vegetable oils with this enzyme preparation, the phosphorus content of the oil became lower than 4 mg/kg after 5 h of enzyme treatment at 40°C. The novel PLC from B. licheniformis MTCC 7445 is potentially useful for the refining of high quality oils with 95% removal of phospholipids with attractive yield.     

Xanthan batch fermentations: compared performances of a bubble column and a stirred tank fermentor

Fermentations of Xanthomonas campestris, NRRL B-1459, were carried out in a bubble column fermentor (BCF) and in a stirred tank fermentor (STF) to allow comparison of representative variables measured during the microbial growth and the gum production. The microbial growth phase was described by a logistic rate equation where maximum cell concentration was provided by nitrogenous compounds balance. The average value of the maximum specific growth rate was higher in the bubble column (μ _M =0.5 h^?1) than in the stirred reactor (μ _M =0.4 h^?1). The upper values of xanthan yield (Y _g-x =0.65 kg xanthan/kg glucose; Y _{O 2?x} xanthan/kg oxygen) and specific production rate (q _x =0.26 kg xanthan/kg biomass · h) were measured when the oxygen transfer coefficient was kept up above 80 h^?1 in the STF fermentor. In the bubble column the fermentation achieved in the same culture medium lasts two times longer than in the stirred aerated tank; this was attributed to the low value of the oxygen transfer coefficient (K _L a =20 h^?1) at the beginning of the gum synthesis phase. The results obtained in the stirred tank were the basis to estimate the optimal biomass concentration which enables to achieve a culture in non-limiting oxygen transfer conditions. Nevertheless, the transfer characteristics were more homogeneous in the bubble column than in the stirred tank where dead stagnant zones were observed. This is of primary importance when establishing fermentation kinetics models.     

Reversible and irreversible conversion between the intermolecular β-structure and the disordered state of poly(s-carboxymethyl-l-cysteine) in aqueous media

Conversion between the intermolecular β-structure and the disordered state of a fractionated low molecular weight sample of poly(S-carboxyniethyl-L-cysteine) was examined mainly by the measurements of circular dichroism in the absence of salt as well as in the presence of 20 mM NaClO₄, or NaCl. In 20 mM NaClO₄ or NaCl solutions, the conversion was reversible. Under this condition, it was confirmed by direct and unambiguous evidence provided from the viscosity and the reduced scattering intensity that the β-structure was formed by intermolecular association. At low degrees of neutralization, the pH increased on dilution while it remained constant over a wide range of concentration at a high degree of neutralization. In the absence of salt, the conversion was often irreversible with respect to a concentration change at a constant degree of neutralization or to a change in the degree of neutralization at a constant concentration. The extent of the irreversible conversion decreased with the amount of β-structure in the solution. The dissociation of aggregates was very slow at low ionic strengths. It was inferred that the irreversible nature of the conversion arose from this slow dissociation of aggregates.     

Pseudozyma sp. SPJ: an economic and eco-friendly approach for degumming of flax fibers

A cellulase free, alkaline, thermo-tolerant pectinase was produced by a novel yeast strain Pseudozyma sp. SPJ using citrus peel as inexpensive carbon source. The crude enzyme showed good prospects in degumming of flax fibers for textile industry. An optimum pectinase dose of 80 U g⁻¹ resulted in reduction of 15 ± 1.92% dry weight of the fibers, releasing maximum galacturonic acid (10825.5 ± 34.2 μg g⁻¹ dry fiber) after the incubation of 6 h. The yeast culture could grow on the flax fibers (as sole carbon source) without addition of any other nutrient and produce good enzyme yield (9235.5 ± 21.51 U g⁻¹ dry fiber). After 12 h incubation of the fibers with the isolated yeast strain, 4471 ± 19.5 μg g⁻¹ dry fiber galacturonic acid was achieved with maximum weight loss of 11 ± 1.2%. This process reduced the amount of chemicals and energy used in conventional methods. It also contributed to enhance fineness and overall quality of the fiber strands. This study is relevant to the textile industry as it provided a fast, economical and eco-friendly method for degumming of flax fibers.     

Effects of drying methods on rheological properties of flaxseed gum

Flaxseed gum solutions were extracted and dried by different methods: ethanol precipitation, freeze drying, 105 °C oven drying, 80 °C oven drying, spray drying, and vacuum drying. The effects of these drying methods on the rheological properties of flaxseed gum were investigated in present study. Ethanol precipitation increased the apparent viscosity of flaxseed gum solution, while all the other methods decreased the apparent viscosity. Most of the drying methods slightly increased the activation energy, except ethanol precipitation. In frequency sweep test, all the drying methods reduced the G′ and G″ values. In creep–recovery tests, the data were modeled by Berger’s model. The E₂ and η₁ values were reduced by all of the drying methods in this study. Some relationships were found between the parameters in the Power Law model of the frequency sweep test and the parameters in Berger’s model.     

Induction and Characterization of Chlorate-resistant Strains of Rosa damascena Cultured Cells

The sensitivity of Rosa damascena cultured cells to chlorate was measured by plating samples of suspensions in agar containing NaClO₃. This sensitivity depended on the age of the cultures that were plated. Chlorate-resistant colonies isolated from 5- to 7-day cultures retained their resistance through many generations of growth in medium lacking NaClO₃; they also retained resistance when mixed with sensitive cells. Treating cell aggregates with ultraviolet (UV) light (254 nanometers), or UV light (360 nanometers) in the presence of 4′-methoxymethyltrioxsalen, increased the proportion that was resistant to NaClO₃. However, the amount of increase was low (three times) and required very specific doses of UV light. The UV treatments did not select for chlorate-resistant cells over chlorate-sensitive cells. The data suggested that UV had induced mutations leading to chlorate resistance. Approximately 15% of the resistant strains did not grow on medium containing nitrate as the sole nitrogen source. These strains lacked ability to reduce chlorate to chlorite. This observation supports the current idea that chlorate toxicity depends on the activity of nitrate reductase. Approximately 85% of the resistant strains grew on medium containing nitrate as the sole nitrogen source. These strains lost catalase activity following chlorate treatment, indicating that they took up and reduced chlorate. These strains have a mechanism for tolerating chlorate and its reduction products, rather than avoiding them.     

Degumming of ramie fibers by alkalophilic bacteria and their polysaccharide-degrading enzymes

Three strains of alkalophilic bacteria, Bacillus sp. NT-39, NT-53 and NT-76, were selected for the degumming of ramie fibers and production of polysaccharide-degrading enzymes. After 48 h of incubation with the strains, the loss of the gum might amount to 5.0% or more of the fibers and a number of polysaccharide-degrading enzymes were secreted to the culture supernatants. The residual gum of the fibers decreased to 9.4% after 5 h of enzymatic degumming. Analysis of gum contents and enzyme activities revealed that pectate lyase and xylanase played an important role in the degradation of residual gum. Enzymatic degumming resulted in an increment of 5.4 ISO units in fiber brightness, whereas the reduction in bundle breaking tenacity of the fibers was less than 5.%. The results confirmed that degumming of ramie fibers by alkalophilic bacteria and their enzymes had substantial advantages.     

Improved gellan gum production by a newly-isolated Sphingomonas azotifigens GL-1 in a cheese whey and molasses based medium

Gellan gum is a water-soluble exopolysaccharide, it has applications in the food, pharmaceutical and chemical industries. In this study, a gellan gum producing strain was isolated from rice root, and this strain was identified be the species of Sphingomonas azotifigens. The Plackett-Burman design was applied to investigate the main factors affecting gellan gum production by S. azotifigens GL-1 in a molasses and cheese whey based medium; the medium compositions were optimized by response surface methodology. The optimum cheese whey based medium consisted of cheese whey 68.34 g/L, Na₂HPO₄ 14.58 g/L and KH₂PO₄ 7.66 g/L, and the maximum gellan gum production that using this medium was 33.75 ± 1.55 g/L. 14.75 ± 0.65 g/L gellan gum was obtained with an optimized molasses medium, which consisted of molasses 50 g/L, Na₂HPO₄ 9.71 g/L and KH₂PO₄ 5.92 g/L. The molecular weight of gellan gum obtained from two medias were 1.06 × 10⁶ and 0.89 × 10⁶ Da, respectively. The cheese whey-derived gellan gum showed a higher rhamnose, lower glucuronic acid and higher glycerate content compared to the molasses-derived gellan gum. S. azotifigens GL-1 has a high gellan gum production capacity in a cheap medium suggesting it has great potential as an industrial gellan gum producer.     

Antifungal activity of alkyl and heterocyclic aza-derivatives of gossypol as well as their complexes with NaClO4 against Fusarium oxysporum f. sp. lupini

Eight alkyl and six heterocyclic aza-derivatives of gossypol (2–15) have been synthesized using gossypol (1) extracted from Gossypium Herbaceum cottonseeds. The ability of gossypol aza-derivatives to form complexes with NaClO₄ has been investigated by electrospray ionisation (ESI) mass spectra recorded in the positive and negative ion detection modes. The gossypol aza-derivatives have been characterized by FT-IR, ¹H and ¹³C NMR spectroscopic methods and subsequently tested for their antifungal properties against Fusarium oxysporum. Four alkyl aza-derivatives (2–5), present in the enamine–enamine tautomeric form, have shown activity comparable or higher than that of gossypol against this fungus. To improve the antifungal activity the complexes of the most active compounds 2–5 with NaClO₄ were prepared. Complexes of 2 and 5 with NaClO₄ have shown antifungal activity higher than that of the uncomplexed compounds.     

A Comparison of the Effects of Ocular Preservatives on Mammalian and Microbial ATP and Glutathione Levels

The aim of this study was to investigate the mechanism of action of the preservative sodium chlorite (NaClO²), and the relationship with intracellular glutathione depletion. A detailed comparison of the dose responses of two cultured ocular epithelial cell types and four species of microorganism was carried out, and comparisons were also made with the quaternary ammonium compound benzalkonium chloride (BAK), and the oxidant hydrogen peroxide (H²O²). The viability of mammalian and microbial cells was assessed in the same way, by the measurement of intracellular ATP using a bioluminescence method. Intracellular total glutathione was measured by reaction with 5,5′-dithiobis-2-nitrobenzoic acid in a glutathione reductase-dependent recycling assay. BAK and H²O² caused complete toxicity to conjunctival and corneal epithelial cells at ～25?ppm, in contrast to NaClO², where >100?ppm was required. The fungi Candida albicans and Alternaria alternata had a higher resistance to NaClO² than the bacteria Staphyloccus aureus and Pseudomonas aeruginosa, but the bacteria were extremely resistant to H²O². NaClO² caused substantial depletion of intracellular glutathione in all cell types, at concentrations ranging from <10?ppm in Pseudomonas, 25–100?ppm in epithelial cells, to >500?ppm in fungal cells. The mechanisms of cytotoxicity of NaClO², H²O² and BAK all appeared to differ. NaClO² was found to have the best balance of high antibacterial toxicity with low ocular toxicity. The lower toxicity of NaClO² to the ocular cells, compared with BAK and H²O², is in agreement with fewer reported adverse effects of application in the eye.     

Variability of Organic Matter Inputs Affects Soil Moisture and Soil Biological Parameters in a European Detritus Manipulation Experiment

Over the last three decades, increased temperatures and reduced annual precipitation have resulted in significant changes in several Central European deciduous forests. These effects include changes in soil moisture content and detritus production. Within the framework of a detritus manipulation experiment carried out in an old-growth Quercetum petraea–cerris community, we examined how changes in detritus inputs affect soil moisture content and microbial activity within six treatments. CO₂ release and microbial enzyme activities are known to be highly sensitive to environmental factors such as soil moisture and detritus inputs. We applied three detritus removal (No Litter, No Roots and No Input) and two detritus addition (Double Litter and Double Wood) treatments. Although the plots received the same amount of precipitation, the various detritus inputs caused significant differences in soil moisture. Treatments excluding living roots had the highest moisture levels, while the treatment excluding only aboveground detritus inputs had the lowest. CO₂ release, arylsulphatase activity and saccharase activity showed significant seasonal differences with the highest values occurring in spring. Moisture content had a significant positive correlation with CO₂ release, and enzyme activities of the plots were affected by the quantity and quality of detritus inputs. Arylsulphatase activity showed the strongest correlation with soil moisture content (R?=?0.62 in the control plot) followed by CO₂ release (R?=?0.61) and finally saccharase activity (R?=?0.42). We observed that there was a remarkably weaker correlation between soil moisture content and the three parameters in the detritus removal treatments (R values between 0.56 and 0.13) than in the Control and detritus addition treatments (R values between 0.72 and 0.42). The correlation between the three parameters of interest and soil moisture content weakens considerably under drought conditions relative to the optimal moisture range of soil moisture content for microbial activity. If the amount of precipitation in the area continues to decrease as anticipated, then litter production and soil microbial activity may be reduced.     

Enzymatic grafting of natural phenols to flax fibres: Development of antimicrobial properties

Unbleached flax fibres for paper production were treated with laccase from Pycnoporus cinnabarinus and low molecular weight phenols (syringaldehyde - SA, acetosyringone - AS and p-coumaric acid - PCA) to evaluate the potential of this treatment to biomodify high cellulose content fibres. After the enzymatic treatment with the phenols, an increase in kappa number was found, probably due to a covalent binding of the phenoxy radicals on fibres. Grafting was more evident in pulps treated with PCA (an increase of 4 kappa number points with respect to the laccase control was achieved). Paper handsheets from treated pulps showed antimicrobial activity against the bacteria tested: Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae. An important reduction on microbial count was obtained after incubation of liquid cultures of the bacteria with grafted handsheets. AS and PCA grafted fibres showed a high antibacterial activity on K. pneumoniae, getting a nearly total growth inhibition. AS fibres also caused a high reduction in bacterial population of P. aeruginosa (97% reduction). Optical properties of handsheets from treated pulps were also determined, showing a brightness decrease and increase in coloration, evaluated by CIE L*a*b* system, caused by the laccase induced grafting of the phenols. The results suggest that these low molecular weight phenols, covalently bound to the flax fibres by the laccase treatment, can act as antimicrobial agents and produce handsheets with antimicrobial activity.     

Changes in Microbial Communities Associated with the Sea Anemone Anemonia viridis in a Natural pH Gradient

Ocean acidification, resulting from rising atmospheric carbon dioxide concentrations, is a pervasive stressor that can affect many marine organisms and their symbionts. Studies which examine the host physiology and microbial communities have shown a variety of responses to the ocean acidification process. Recently, several studies were conducted based on field experiments, which take place in natural CO₂ vents, exposing the host to natural environmental conditions of varying pH. This study examines the sea anemone Anemonia viridis which is found naturally along the pH gradient in Ischia, Italy, with an aim to characterize whether exposure to pH impacts the holobiont. The physiological parameters of A. viridis (Symbiodinium density, protein, and chlorophyll a+c concentration) and its microbial community were monitored. Although reduction in pH was seen to have had an impact on composition and diversity of associated microbial communities, no significant changes were observed in A. viridis physiology, and no microbial stress indicators (i.e., pathogens, antibacterial activity, etc.) were detected. In light of these results, it appears that elevated CO₂ does not have a negative influence on A. viridis that live naturally in the site. This suggests that natural long-term exposure and dynamic diverse microbial communities may contribute to the acclimation process of the host in a changing pH environment.     

The relationship of the quaternary structure of allophycocyanin to its spectrum

Allophycocyanin II in its trimer form (α₃β₃) at pH 7.0 has an absorption maximum at 652 nm. This band is selectively reduced in intensity at pH 7.0 when various salts are added. The loss of 652 nm absorption follows the order: NaClO₄ ? NaNO₃ > NaBr > NaCl. When the NaClO₄ concentration is in the range 0.6-1.0 m the 652-nm band is entirely lost, and sedimentation equilibrium and velocity studies suggest that the trimer is completely dissociated to monomers (αβ). Hydrophobic interactions appear to be important in maintaining the trimer. The monomer absorption maximum is at 616 nm. A series of experiments using these salts demonstrated at intermediate 652-nm intensities and the two extrema that an isobestic point at 626 nm is present which indicates an equilibrium between two species. Corresponding to the loss of 652 nm absorption is the disappearance of 661 nm fluorescence emission and the appearance of a new band at 642 nm. Removal of the NaClO₄ by dialysis essentially restores the 652-nm absorption and 661-nm emission and the trimeric protein structure. The near ultraviolet region is only slightly perturbed during the loss of 652 nm absorption. In the absence of any additional salts these spectral changes also occur in pH 7.0 buffer at very low protein concentrations.     

Effect of particle size and microbial phytase on phytate degradation in incubated maize and soybean meal

The objective of the study was to evaluate the effect of screen size (1, 2 and 3 mm) and microbial phytase (0 and 1000 FTU/kg as-fed) on phytate degradation in maize (100% maize), soybean meal (100% SBM) and maize–SBM (75% maize and 25% SBM) incubated in water for 0, 2, 4, 8 and 24 h at 38°C. Samples were analysed for pH, dry matter and phytate phosphorus (P). Particle size distribution (PSD) and average particle size (APS) of samples were measured by the Laser Diffraction and Bygholm method. PSD differed between the two methods, whereas APS was similar. Decreasing screen size from 3 to 1 mm reduced APS by 48% in maize, 30% in SBM and 26% in maize–SBM. No interaction between screen size and microbial phytase on phytate degradation was observed, but the interaction between microbial phytase and incubation time was significant (P<0.001). This was because microbial phytase reduced phytate P by 88% in maize, 84% in maize–SBM and 75% in SBM after 2 h of incubation (P<0.05), whereas the reduction of phytate P was limited (<50%) in the feeds, even after 24 h when no microbial phytase was added. The exponential decay model was fitted to the feeds with microbial phytase to analyse the effect of screen size and feed on microbial phytase efficacy on phytate degradation. The interaction between screen size and feed affected the relative phytate degradation rate (R_d) of microbial phytase as well as the time to decrease 50% of the phytate P (t1/2) (P<0.001). Thus, changing from 3 to 1 mm screen size increased R_d by 22 and 10%/h and shortened t1/2 by 0.4 and 0.2 h in maize and maize–SBM, respectively (P<0.05), but not in SBM. Moreover, the screen size effect was more pronounced in maize and maize–SBM compared with SBM as a higher phytate degradation rate constant (K_d) and R_d, and a shorter t1/2 was observed in maize compared with SBM in all screen sizes (P<0.05). However, a higher amount of degraded phytate was achieved in SBM than in maize because of the higher initial phytate P content in SBM. In conclusion, reducing screen size from 3 to 1 mm increased K_d and R_d and decreased t1/2 in maize and maize–SBM with microbial phytase. The positive effect of grinding on improving microbial phytase efficacy, which was expressed as K_d, R_d and t1/2, was greater in maize than in SBM.     

Effects of Hofmeister ions on the α-helical structure of proteins

The molecular conformation of proteins is sensitive to the nature of the aqueous environment. In particular, the presence of ions can stabilize or destabilize (denature) protein secondary structure. The underlying mechanisms of these actions are still not fully understood. Here, we combine circular dichroism (CD), single-molecule Förster resonance energy transfer, and atomistic computer simulations to elucidate salt-specific effects on the structure of three peptides with large α-helical propensity. CD indicates a complex ion-specific destabilization of the α-helix that can be rationalized by using a single salt-free computer simulation in combination with the recently introduced scheme of ion-partitioning between nonpolar and polar peptide surfaces. Simulations including salt provide a molecular underpinning of this partitioning concept. Furthermore, our single-molecule Förster resonance energy transfer measurements reveal highly compressed peptide conformations in molar concentrations of NaClO₄ in contrast to strong swelling in the presence of GdmCl. The compacted states observed in the presence of NaClO₄ originate from a tight ion-backbone network that leads to a highly heterogeneous secondary structure distribution and an overall lower α-helical content that would be estimated from CD. Thus, NaClO₄ denatures by inducing a molten globule-like structure that seems completely off-pathway between a fully folded helix and a coil state.     

Colonization of Flax Roots and Early Physiological Responses of Flax Cells Inoculated with Pathogenic and Nonpathogenic Strains of Fusarium oxysporum

Fusarium oxysporum includes nonpathogenic strains and pathogenic strains that can induce necrosis or tracheomycosis in plants. The objective of this study was to compare the abilities of a pathogenic strain (Foln3) and a nonpathogenic strain (Fo47) to colonize flax roots and to induce early physiological responses in flax cell culture suspensions. Both strains colonized the outer cortex of the root; however, plant defense reactions, i.e., the presence of wall appositions, osmiophilic material, and collapsed cells, were less frequent and less intense in a root colonized by Foln3 than by Fo47. Early physiological responses were measured in flax cell suspensions confronted with germinated microconidia of both strains. Both pathogenic (Foln3) and nonpathogenic strains (Fo47) triggered transient H₂O₂ production in the first few minutes of the interaction, but the nonpathogenic strain also induced a second burst 3 h postinoculation. Ca²⁺ influx was more intense in cells inoculated with Fo47 than in cells inoculated with Foln3. Similarly, alkalinization of the extracellular medium was higher with Fo47 than with Foln3. Inoculation of the fungi into flax cell suspensions induced cell death 10 to 20 h postinoculation, with a higher percentage of dead cells observed with Fo47 than with Foln3 beginning at 14 h. This is the first report showing that early physiological responses of flax cells can be used to distinguish pathogenic and nonpathogenic strains of the soil-borne fungus F. oxysporum.     

Quantifying of bactericide properties of medicinal plants

Extended research has been carried out to clarify the ecological role of plant secondary metabolites (SMs). Although their primary ecological function is self-defense, bioactive compounds have long been used in alternative medicine or in biological control of pests. Several members of the family Labiatae are known to have strong antimicrobial capacity. For testing and quantifying antibacterial activity, most often standard microbial protocols are used, assessing inhibitory activity on a selected strain. In this study, the applicability of a microbial ecotoxtest was evaluated to quantify the aggregate bactericide capacity of Labiatae species, based on the bioluminescence inhibition of the bacterium Vibrio fischeri. Striking differences were found amongst herbs, reaching even 10-fold toxicity. Glechoma hederacea L. proved to be the most toxic, with the EC₅₀ of 0.4073 g dried plant/l. LC₅₀ values generated by the standard bioassay seem to be a good indicator of the bactericide property of herbs. Traditional use of the selected herbs shows a good correlation with bioactivity expressed as bioluminescence inhibition, leading to the conclusion that the Vibrio fischeri bioassay can be a good indicator of the overall antibacterial capacity of herbs, at least on a screening level.Key words: Labiatae, antibacterial property, bioactivity, Vibrio fischeri