Bacillus Licheniformis Strain Research Articles

Efficacy of probiotic Bacillus licheniformis DSM 28710 on performance and the mitigation of Clostridium perfringens-induced necrotic enteritis in broiler chickens

The aim of this study was to evaluate the impact of a probiotic Bacillus licheniformis strain (DSM 28710; B-Act®) on growth performance and its capacity to mitigate necrotic enteritis (NE; induced via a Clostridium perfringens challenge) in poultry. A broiler trial was conducted, examining three treatments for 42 days under an induced NE challenge; a negative control (basal diet only); an antibiotic treated group (oxytetracycline hydrochloride (OXT), therapeutic dose of 105 mg OXT/litre in drinking water, for three days after C. perfringens challenge); and a B-Act group (500 g B-Act/tonne of feed, equalling 1.6×1012 colony forming units B. licheniformis DSM 28710/tonne of feed, supplemented from start until finish). Despite the induced NE challenge, weight gains of the B-Act and OXT groups were similar to each other but significantly higher compared to the control at the end of the study (P<0.05). Weight gain of the B-Act group was already significantly higher compared to the control on day 21 (P<0.05), indicating a potential benefit of the probiotic even before clinical establishment of NE. Feed conversion ratio (FCR) values followed a similar pattern throughout the study, with a significantly lower overall FCR for the B-Act and OXT groups compared to the control (P<0.05; d0-42). Birds fed B-Act had significantly (P<0.05) lower NE lesions compared to the control and OXT group on day 21, although OXT was not supplemented to the animals at this stage yet. Both B-Act and OXT groups had significantly (P<0.05) lower NE scores than the control on day 28, demonstrating the effectiveness of the antibiotic treatment and the mitigating effect of B-Act on the effects of a Clostridium perfringens induced NE challenge.

Fermentation time-dependent pectinase activity is associated with metabolomics variation in Bacillus licheniformis DY2

Fermentation conditions affect pectinase production. Among these conditions, fermentation period is one of the important parameters to be optimized for saving the process costs. However, information regarding whether metabolic regulation plays a role is not available. Here, a Bacillus licheniformis strain DY2 was incubated in submerged fermentation for pectinase production for 48 h. The pectinase activity was assayed every 4 h from 8th h of fermentation. The pectinase activity was low at 8 h, middle at 28 h, and peak at 44 h. Consistently, metabolomics analysis showed that the metabolic shift is related to the fermentation period. The metabolomes exhibited almost of differential metabolites in the enriched metabolic pathways, which were decreased at 28 h and 44 h compared to 8 h in a time-dependent manner. Furthermore, reduced palmitic acid and stearic acid in a time-dependent manner were identified as crucial biomarkers at 48 h. These findings in our work reveal that the reduced fatty acid biosynthesis is required for pectinase yield, which was further demonstrated by addition of inhibitors furfural and triclosan to inhibit pyruvate dehydrogenase and fatty acid biosynthesis, respectively. Our work reveals a potential possibility to elevate pectinase yield through metabolomics modulation.

Identification and Characterization of a Newly Isolated Chitinase-Producing Strain Bacillus licheniformis SSCL-10 for Chitin Degradation.

Chitinases or chitinolytic enzymes have different applications in the field of medicine, agriculture, and industry. The present study is aimed at developing an effective hyperchitinase-producing mutant strain of novel Bacillus licheniformis. A simple and rapid methodology was used for screening potential chitinolytic microbiota by chemical mutagenesis with ethylmethane sulfonate and irradiation with UV. There were 16 mutant strains exhibiting chitinase activity. Out of the chitinase-producing strains, the strain with maximum chitinase activity was selected, the protein was partially purified by SDS-PAGE, and the strain was identified as Bacillus licheniformis (SSCL-10) with the highest specific activity of 3.4 U/mL. The induced mutation model has been successfully implemented in the mutant EMS-13 (20.2 U/mL) that produces 5-6-fold higher yield of chitinase, whereas the mutant UV-11 (13.3 U/mL) has 3-4-fold greater chitinase activity compared to the wild strain. The partially purified chitinase has a molecular weight of 66 kDa. The wild strain (SSCL-10) was identified as Bacillus licheniformis using 16S rRNA sequence analysis. This study explores the potential applications of hyperchitinase-producing bacteria in recycling and processing chitin wastes from crustaceans and shrimp, thereby adding value to the crustacean industry.

Isolation and Molecular Characterization of Antibiotic Producing Bacillus licheniformis Strains Isolated from Soil

Currently, there is an increase prevalence of antibiotic-resistant bacteria worldwide. Therefore, the need for characterization of naturally occuring antibiotics with less antibiotic resistance is required. Soil resources contains valuable antibiotic producing microorganisms that increasingly being utilized for the production of suitable antibiotics. Therefore, this study aimed at identifying an antibiotic bacteria with ability of producing antibiotic that is isolated from soil samples collected from Al Zarqa provenance, an arid area in Jordan. Morphological and biochemical characterization of the isolates were carried out and found that all of the isolates belong to Bacillus genus. Further confirmation of the characterization of the bacteria was done by ribosomal RNA and PCR. The results reveal that the isolates represent Basilluslicheniformis. These bacilli were further investigated for antimicrobial activities against 6 ATCC human pathogens viz., S. aureus, S. pneumonia, Salmonella typhi., E. coli, P. mirabels and E. cloacae. Additionally, the results of Gas Chromatography Mass Spectrometry (GCMS) of ethyl acetate extracts for B. licheniformis secondary metabolites showed that they contain two main antimicrobial compounds namely Pyrrolo [1, 2-a] pyrazine-1, 4-dione,hexahydro and Trans-13-octadecenoic acid. The present work maybe suggests that soil isolates from the studied arid area include antibiotic producing strains that can be utilized commercially.

Discovery of Novel Prebiotic Carbohydrates and Sugar Mimics of BlMsmE, a Solute-Binding Protein of the ABC Transporter from Bacillus licheniformis.

Stachyose is a typical prebiotic that can be utilized by the probiotic strain Bacillus licheniformis. Pioneering X-ray crystallography has determined the structure of stachyose in complex with the solute-binding protein MsmE in B. licheniformis (BlMsmE). The present work describes a combined strategy for the identification of putative BlMsmE-specific ligands, which can be used for the development of prebiotics. After a ligand-based virtual similarity screening of a large ZINC database containing ∼22 M compounds, we identified 3575 ligands. A total of 600 structures for which the Tanimoto coefficient's value was larger than a cutoff of 0.23 were selected for molecular docking. Based on the docking scores, we identified 100 top-scoring ligands, followed by molecular dynamics (MD) simulations. During simulations, 35 candidates were abandoned because of serious steric clashes in the complexes. Finally, the top 10 ligands with free energies below an energy threshold of -50.84 kcal/mol were selected. The top two ligands were stachyose and raffinose, which have proved their health benefits as prebiotics and their safety. The remaining eight ligands were further analyzed by the in silico ADME tool; only galactinol did not violate any of the criteria required for a lead compound. These three ligands were further analyzed for understanding their binding to BlMsmE. Isothermal titration calorimetry analysis suggested that stachyose, raffinose, and galactinol bound strongly to BlMsmE with Kd values of 299, 170, and 134 nM, respectively. Microsecond MD simulations suggested significant conformational changes of BlMsmE upon ligand binding. Our results provide new insight into the thermodynamics of sugars and MsmE, which would promote the development of novel prebiotics.

Safety evaluation of the food enzyme α-amylase from the genetically modified Bacillus licheniformis strain DP-Dzb45.

The food enzyme α‐amylase (1,4‐α‐D‐glucan glucanohydrolase; EC 3.2.1.1) is produced with the genetically modified Bacillus licheniformis strain DP‐Dzb45 by Danisco US Inc. The production strain of the food enzyme contains multiple copies of an antimicrobial resistance gene. However, based on the absence of viable cells and DNA from the production organism in the food enzyme, this was not considered to be a risk. The α‐amylase is intended to be used in brewing processes and distilled alcohol production. Since residual amounts of the food enzyme are removed by distillation, no dietary exposure was calculated for this intended use. Based on the maximum use levels recommended for the brewing processes and individual data from the EFSA Comprehensive European Food Consumption Database, dietary exposure to the food enzyme–total organic solids (TOS) was estimated to be up to 0.138 mg TOS/kg body weight per day in European populations. Toxicological tests with the food enzyme indicated that there was no concern with respect to genotoxicity or systemic toxicity. A no observed adverse effect level was identified in rats, which, compared with the dietary exposure, results in a margin of exposure of at least 484. Similarity of the amino acid sequence to those of known allergens was searched and one match was found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions can be excluded in distilled alcohol production but cannot be excluded when the enzyme is used in brewing. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Bacillus licheniformis strain POT1 mediated polyphenol biosynthetic pathways genes activation and systemic resistance in potato plants against Alfalfa mosaic virus

Alfalfa mosaic virus (AMV) is a worldwide distributed virus that has a very wide host range and causes significant crop losses of many economically important crops, including potato (Solanum tuberosum L.). In this study, the antiviral activity of Bacillus licheniformis strain POT1 against AMV on potato plants was evaluated. The dual foliar application of culture filtrate (CF), 24 h before and after AMV-inoculation, was the most effective treatment that showed 86.79% reduction of the viral accumulation level and improvement of different growth parameters. Moreover, HPLC analysis showed that a 20 polyphenolic compound was accumulated with a total amount of 7,218.86 and 1606.49 mg/kg in POT1-treated and non-treated plants, respectively. Additionally, the transcriptional analysis of thirteen genes controlling the phenylpropanoid, chlorogenic acid and flavonoid biosynthetic pathways revealed that most of the studied genes were induced after POT1 treatments. The stronger expression level of F3H, the key enzyme in flavonoid biosynthesis in plants, (588.133-fold) and AN2, anthocyanin 2 transcription factor, (97.005-fold) suggested that the accumulation flavonoid, especially anthocyanin, might play significant roles in plant defense against viral infection. Gas chromatography-mass spectrometry (GC-MS) analysis showed that pyrrolo[1,2-a]pyrazine-1,4-dione is the major compound in CF ethyl acetate extract, that is suggesting it acts as elicitor molecules for induction of systemic acquired resistance in potato plants. To our knowledge, this is the first study of biological control of AMV mediated by PGPR in potato plants.

Isolation, Characterization, and Molecular Identification of Indigenous Bacteria from Fermented Almonds (Prunus dulcis)

Aims: This study aims to isolate and identify the indigenous bacteria of almonds fermentation.
 Methods: Characterization of the indigeneous bacteria are using gram staining, biochemical tests, 16SrRNA gene sequencing, and the antimicrobial activity against Escherichia coli bacteria.
 Results: Approximately 28 x 106 CFU / mL bacteria were obtained from almonds fermentations with 14 isolates from enrichment results. Three randomly selected isolates were gram-positive rod-shaped with a negative catalase and positive fermentation test. However, one isolate showed positive results on the motility test. The antimicrobial test results from the three randomly selected isolates using the disk diffusion method obtained inhibition zones of 7 mm, 6.7 mm, and 7 mm, respectively. Therefore, by using 16S rRNA gene sequencing, three different microorganisms were found, namely Bacillus subtilis strain IAM 12118, Bacillus Piscis strain 16MFT21, and Bacillus licheniformis strain BaDB27.
 Conclusion: It was found that Bacillus subtilis strain IAM 12118, Bacillus Piscis strain 16MFT21, and Bacillus licheniformis strain BaDB27 in almonds fermentation and also can be used as probiotic bacteria.

Phylogenetic characterization and screening of halophilic bacteria from Algerian salt lake for the production of biosurfactant and enzymes

Environments containing significant concentration of NaCl such as salt lakes harbor extremophiles microorganisms which have a great biotechnology interest. To explore the diversity of Bacteria in Chott Tinsilt (Algeria), an isolation program was performed. Water samples were collected from the saltern during the pre-salt harvesting phase. This Chott is high in salt (22.47% (w/v). Seven halophiles Bacteria were selected for further characterization. The isolated strains were able to grow optimally in media with 10–25% (w/v) total salts. Molecular identification of the isolates was performed by sequencing the 16S rRNA gene. It showed that these cultured isolates included members belonging to the Halomonas, Staphylococcus, Salinivibrio, Planococcus and Halobacillus genera with less than 98% of similarity with their closest phylogenetic relative. The halophilic bacterial isolates were also characterized for the production of biosurfactant and industrially important enzymes. Most isolates produced hydrolases and biosurfactants at high salt concentration. In fact, this is the first report on bacterial strains (A4 and B4) which were a good biosurfactant and coagulase producer at 20% and 25% ((w/v)) NaCl. In addition, the biosurfactant produced by the strain B4 at high salinity (25%) was also stable at high temperature (30-100°C) and high alkalinity (pH 11).

Distribution and molecular characterization of biosurfactant-producing bacteria

Abstract. Alyousif NA, Luaibi YYYA, Hussein W. 2020. Distribution and molecular characterization of biosurfactant-producing bacteria. Biodiversitas 21: 4034-4040. Biosurfactants (BSs) are biological surface-active compounds produced by several microorganisms with many areas of application, as such become an important product in biotechnology and consequence to be used in industries. In recent years, many researchers pay attention to BSs producers' microorganisms. The present study was aimed to isolate, identify, and screening BS producing bacteria from six various sites in two different cities in Iraq. Four samples were collected from four sites in Basrah governorate and the rest two samples from Al-Garraf oilfield in Thi-Qar governorate. A total of 33 different bacterial isolates were obtained, 20 out of the 33 were found to be biosurfactants producing isolates that detected through the emulsification index (E24%), oil spreading test, and emulsification activity. The isolated bacterial strains were more identified by 16S rRNA gene sequencing. The results showed that the biosurfactants producing isolates belonged to genera Bacillus, Pseudomonas, Enterobacter, Staphylococcus, Acinetobacter, and Aerococcus. Bacillus jeotgali and Aerococcus viridans are reporting as biosurfactant producing bacteria for the first time and Bacillus jeotgali is isolated for first time from crude oil of oilfield reservoir in this study in world. Moreover, six bacterial isolates were identified as new strains and deposited at NCBI Genbank under accession numbers MT261834 (Bacillus subtilis strain IRQNWYA3), MT261835 (Bacillus licheniformis strain IRQNWYB4), MT261836 (Pseudomonas stutzeri strain IRQNWYF2), MT261837 (Pseudomonas zhaodongensis strain IRQNWYF3), MT261838 (Pseudomonas sp. IRQNWYF4) and MT261839 (Bacillus licheniformis strain IRQNWYF5). A2 isolate that was identified as Pseudomonas aeruginosa has shown the highest values of emulsification activity and emulsification index (1.678±0.050 absorbance at 540 nm and 56.6% respectively) that show efficient potential of biosurfactant production. Phylogenetic tree was also constructed in this study based on 16S rRNA gene sequences of biosurfactant-producing bacteria to evaluate their close relationship and evolution between them.

Safety evaluation of the food enzyme phospholipase C from the genetically modified Bacillus licheniformis strain NZYM-VR.

The food enzyme phospholipase C (phosphatidylcholine cholinephosphohydrolase EC 3.1.4.3) is produced with the genetically modified Bacillus licheniformis strain NZYM‐VR by Novozymes A/S. The genetic modifications do not give rise to safety concerns. The food enzyme is free from viable cells of the production organism and its DNA. This phospholipase C is intended for use in degumming of fats and oils. The residual amounts of Total Organic Solids (TOS) are removed during washing and purification steps applied during degumming. Consequently, no dietary exposure was calculated. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90‐day oral toxicity study in rats. The Panel identified a No Observed Adverse Effect Level (NOAEL) at the highest dose tested of 714 mg TOS/kg body weight (bw) per day. Similarity of the amino acid sequence to those of known allergens was searched for and no match was found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions by dietary exposure cannot be excluded, but the likelihood is considered to be low. Based on the data provided and the removal of TOS during the degumming of fats and oils, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

A novel exopolysaccharide-producing and long-chain n-alkane degrading bacterium Bacillus licheniformis strain DM-1 with potential application for in-situ enhanced oil recovery

A novel Bacillus licheniformis strain (DM-1) was isolated from a mature reservoir in Dagang oilfield of China. DM-1 showed unique properties to utilize petroleum hydrocarbons and agroindustrial by-product (molasses) for exopolysaccharide (EPS) production under oil recovery conditions. The DM-1 EPS was proven to be a proteoglycan with a molecular weight of 568 kDa. The EPS showed shear thinning properties and had high viscosities at dilute concentrations (<1%, w/v), high salinities, and elevated temperatures. Strain DM-1 could degrade long-chain n-alkanes up to C36. Viscosity reduction test have shown that the viscosity of the crude oil was reduced by 40% compared with that before DM-1 treatment. Sand pack flooding test results under simulated reservoir conditions have shown that the enhanced oil recovery efficiency was 19.2% after 7 days of in-situ bioaugmentation with B. licheniformis DM-1. The obtained results indicate that strain DM-1 is a promising candidate for in situ microbial enhanced oil recovery (MEOR).

Characterization and Identification of Naphthalene Degrading Bacteria Isolated from Petroleum Contaminated Sites and Their Possible Use in Bioremediation

Naphthalene is a simple polycyclic aromatic hydrocarbon (PAH) regarded as a common environmental pollutant. A total number of 16 bacterial isolates obtained from various petroleum contaminated sites of Gwalior (MP), India were screened for their naphthalene degradation potential. Enrichment method was used for the isolation of bacteria by amending the medium with 100 mg l−1 naphthalene dissolved in acetone. Out of 16 bacterial isolates, only two isolates designated as RS2(3) and GS2 have shown a good naphthalene degradation potential based on maximum tolerance level at 1000 mg l−1 and growth of the isolates as 0.536 and 0.133, respectively measured in terms of optical density (OD) at 600 nm. The degradation was determined by GC analysis, GS2 showed 73% and 48% degradation, while RS2(3) showed 52% and 29% at 100 and 200 mg l−1 naphthalene concentration, respectively. The isolates were also characterized for their heavy metal tolerance against four selected heavy metals (Cadmium, Chromium, Copper and Zinc) at different concentrations (0.1%, 0.5% and 1.0%). Out of total 16 bacterial isolates only twelve were found resistant to one percent concentration of any one of the four heavy metals. Moreover, the antibiotic sensitivity of the isolates was also determined against four different antibiotics. These isolates were characterized morphologically, biochemically and identified as strain Bacillus licheniformis JUG GS2 (MK106145) and Bacillus sonorensis JUG (RS2(3)) (MK156710) by 16S rRNA gene sequencing. The study infers that Bacillus licheniformis and Bacillus sonorensis strains can be helpful to remediate contaminations attributed to naphthalene and heavy metals as well.

Production of detergent stable thermophilic alkaline protease by Bacillus licheniformis ALW1

The growing industrial applications of alkaline proteases urged the production of highly active stable enzymes. In the current study, the enzyme production was achieved by submerged fermentation using the bacterial strain Bacillus licheniformis ALW1 that was further optimized to reach 22.903U/mL. The overall optimization fold was 46.7, achieved under the optimized fermentation medium composed of (%) molasses ; 8, (NH 4 ) 2 SO 4 ; 0.45, wheat bran ; 5, MgSO4·7H 2 O; 0.2, KH 2 PO 4 ; 0.4, NaCl; 0.2 adjusted at pH 8 and incubated for 7days at 37 °C and 280 rpm. Additionally, the enzyme activity after partial purification was optimized by studying the effect of pH and temperature as well as the substrate concentration . The results indicated that the enzyme optimum activity was achieved at pH 9 and 70 °C with K m , V max and K cat values of 3.846 mg/mL, 76.923U/mL/min and 1.206min −1 respectively. Thermal stability study of the partial pure enzyme indicated the half live times of the enzyme as 693.15, 231.05 and 57.76 min −1 at 55, 60 and 65 °C respectively, confirming its thermo-stability. Finally, the efficacy of the partial pure enzyme as a detergent additive was examined. The enzyme retained more than 80% of its activity with an efficient washing performance in the removal of blood stain after 30 min at 50 °C in addition to a commercial detergent. • Economic production of highly active alkaline protease using Bacillus licheniformis ALW1. • The partial pure enzyme was thermophilic and possessed high stability in commercial detergent. • The enzyme was added in the detergent formulation and applied for the removal of blood stain.

Two genes involved in clindamycin resistance of Bacillus licheniformis and Bacillus paralicheniformis identified by comparative genomic analysis.

We evaluated the minimum inhibitory concentrations of clindamycin and erythromycin toward 98 Bacillus licheniformis strains isolated from several types of fermented soybean foods manufactured in several districts of Korea. First, based on recent taxonomic standards for bacteria, the 98 strains were separated into 74 B. licheniformis strains and 24 B. paralicheniformis strains. Both species exhibited profiles of erythromycin resistance as an acquired characteristic. B. licheniformis strains exhibited acquired clindamycin resistance, while B. paralicheniformis strains showed unimodal clindamycin resistance, indicating an intrinsic characteristic. Comparative genomic analysis of five strains showing three different patterns of clindamycin and erythromycin resistance identified 23S rRNA (adenine 2058-N6)-dimethyltransferase gene ermC and spermidine acetyltransferase gene speG as candidates potentially involved in clindamycin resistance. Functional analysis of these genes using B. subtilis as a host showed that ermC contributes to cross-resistance to clindamycin and erythromycin, and speG confers resistance to clindamycin. ermC is located in the chromosomes of strains showing clindamycin and erythromycin resistance and no transposable element was identified in its flanking regions. The acquisition of ermC might be attributable to a homologous recombination. speG was identified in not only the five genome-analyzed strains but also eight strains randomly selected from the 98 test strains, and deletions in the structural gene or putative promoter region caused clindamycin sensitivity, which supports the finding that the clindamycin resistance of Bacillus species is an intrinsic property.

Characterization of carbaryl-degrading strain Bacillus licheniformis B-1 and its hydrolase identification.

Pesticides introduced inadvertently or deliberately into environment by anthropogenic activity have caused growing global public concern, therefore the search of approaches for elimination of such xenobiotics should be encouraged. A cypermethrin-degrading bacterial strain Bacillus licheniformis B-1 was found to efficiently degrade carbaryl in LB medium at concentrations of 50-300mg L-1 within 48h, during which temperature and pH played important roles as reflected by increase in pollutant depletion. A stimulatory effect of Fe3+ and Mn2+ on microbial growth was observed, whereas Cu2+ caused inhibition of degradation. Results showed that 1-naphthol was a major transformation product of carbaryl which was further metabolised. An approximately 29kDa carbaryl-degrading enzyme was purified from B-1 with 15.93-fold purification and an overall yield of 6.02% was achieved using ammonium sulphate precipitation, DEAE-Sepharose CL-6B anion-exchange chromatography and Sephadex G-100 gel filtration. The enzyme was identified through nano reversed-phase liquid chromatography coupled with hybrid triple quadrupole time-of-flight mass spectrometry as a phosphodiesterase (PDE). This is the first report on the characterization of carbaryl-degrading by Bacillus spp. and the role of a PDE in carbaryl-detoxifying. Also, strain B-1 showed versatile in carbosulfan, isoprocarb and chlorpyrifos degradation, demonstrating as ideal candidate for environment bioremediation.

Isolation and Characterization of a Deoxynivalenol-Degrading Bacterium Bacillus licheniformis YB9 with the Capability of Modulating Intestinal Microbial Flora of Mice.

Deoxynivalenol (DON) is one of the most prevalent food- and feed-associated mycotoxins. It frequently contaminates agricultural commodities and poses serious threats to human and animal health and leads to tremendous economic losses globally. Much attention has been paid to using microorganisms to detoxify DON. In this study, a Bacillus licheniformis strain named YB9 with a strong ability to detoxify DON was isolated and characterized from a moldy soil sample. YB9 could degrade more than 82.67% of 1 mg/L DON within 48 h at 37 °C and showed strong survival and DON degradation rate at simulated gastric fluid. The effects of YB9 on mice with DON intragastrical administration were further investigated by biochemical and histopathological examination and the gut microbiota was analyzed by 16S rRNA Illumina sequencing technology. The results showed that DON increased the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and creatinine (Cr), decreased those of immunoglobulin G (IgG) and IgM in serum, and resulted in severe pathological damage of the liver, kidney, and spleen. By contrast, YB9 supplementation obviously inhibited or attenuated the damages caused by DON in mice. In addition, YB9 addition repaired the DON-induced dysbiosis of intestinal flora, characterized by recovering the balance of Firmicutes and Bacteroidetes to the normal level and decreasing the abundance of the potentially harmful bacterium Turicibacter and the excessive Lactobacillus caused by DON. Taken together, DON-degrading strain YB9 might be used as potential probiotic additive for improving food and feed safety and modulating the intestinal microbial flora of humans and animals.

Statistical optimization and characterization of bacterial cellulose produced by isolated thermophilic Bacillus licheniformis strain ZBT2

Bacterial cellulose (BC) is an excellent natural biopolymer with wide range of applications. The present study reports a potential BC producing thermophile, identified as Bacillus licheniformis strain ZBT2. The thermophile produced pellicle form of BC (3.0 g/l) under static conditions. Statistical optimization of BC was carried out by Plackett–Burman and central composite design. Results suggest that BC yield (9.2 g/l) was enhanced with 6.6-fold after optimization. BC-gelatin hydrogels composites were developed to assess various properties. The water retention capability and moisture content properties of BC and composites were promising and also exhibited negligible protein adsorption. The composites also demonstrated to be consistent during controlled drug delivery profiling. Furthermore, the composites also demonstrated antibacterial efficiency against Escherichia coli and Micrococcus luteus. The structural, morphological and thermal properties were assessed by analytical techniques such as, fourier transform infrared spectroscopy, scanning electron microscopy with energy dispersive X-ray analysis, thermogravimetric analysis and differential scanning calorimetry analysis. The study reflects the exploitation of a thermophile for development of BC which can be a preferred choice as a scaffold for tissue engineering and drug-delivery systems.

Termiticidal activity of chitinase enzyme of Bacillus licheniformis, a symbiont isolated from the gut of Globitermes sulphureus worker

Abstract Chitinase is a digestive enzyme that breaks down glycosidic bonds in chitin. Chitin is a biopolymer that can be found in the exoskeleton of insects, fungi, yeast, and algae, and in the internal structures of other vertebrates. Bacillus licheniformis strain USMW10IK was isolated from the guts of Globitermes sulphureus workers. The production of chitinase was highest during the stationary phase (72–96 h of incubation) with the enzyme activity was 0.0057 U/mL – 0.0058 U/mL. The crude chitinase extracted after 72 h was used as biotermiticide against termite G. sulphureus. A pathogenic bioassay was done in four methods; no choice, treated sand medium, topical (Petri dish lined with filter paper), and topical (Petri dish lined with sterile sand). Termite mortality was observed for 24–48 h as the crude chitinase stability has decreased by 22.8% after 48 h. As a result, topical (Petri dish lined with filter paper) has caused significant termite mortality after 24 h and topical (Petri dish line with sterile sand) gave significant termite mortality after 48 h while no choice and sand treated medium gave no significant mortality. These findings suggest that chitinase is effective to be used as a biotermiticide when it directly contacts with the termite skin.

Inhibitory effects of Bacillus licheniformis BL06 on Phytophthora capsici in pepper by multiple modes of action

Phytophthora capsici is a pathogenic oomycete that affects pepper cultivation and other commercial products, causing serious economic losses. Here, Bacillus licheniformis strain BL06 effectively reduced pepper Phytophthora blight severity. BL06 suppressed P. capsici mycelium growth by 70% in dual culture tests and induced excessive branching and significant lysis of P. capsici hyphae. The BL06 bacterial culture also inhibited in vitro sporangia development in a dose-dependent manner. Moreover, BL06 inhibited motility and displayed lytic activities against zoospores of P. capsici in a dose- and time-dependent manner. Indeed, the P. capsici infectiousness was reduced in host tissue treated by BL06, which is possibly associated with its ability to inhibit zoospore germination and germ tube growth in host tissues. Collectively, our results demonstrate the utility B. licheniformis BL06 as a potential biocontrol agent for the management of Phytophthora blight of peppers.