Efficient production of L-asparaginase in Bacillus licheniformis by optimizing expression elements and host / 生物工程学报

L-asparaginase (L-ASN) is widely applied in the treatment of malignant tumor and low-acrylamide food production, however, the low expression level hampers its application. Heterologous expression is an effective strategy to increase the expression level of target enzymes, and Bacillus is generally used as the host for efficient production of enzymes. In this study, the expression level of L-asparaginase in Bacillus was enhanced through optimization of expression element and host. Firstly, five signal peptides (SPSacC, SPAmyL, SPAprE, SPYwbN and SPWapA) were screened, among which SPSacC showed the best performance, reaching an activity of 157.61 U/mL. Subsequently, four strong promoters (P43, PykzA-P43, PUbay and PbacA) from Bacillus were screened, and tandem promoter PykzA-P43 showed the highest yield of L-asparaginase, which was 52.94% higher than that of control strain. Finally, three Bacillus expression hosts (B. licheniformis Δ0F3 and BL10, B. subtilis WB800) were investigated, and the maximum L-asparaginase activity, 438.3 U/mL, was reached by B. licheniformis BL10, which was an 81.83% increase compared with that of the control. This is also the highest level of L-asparaginase in shake flask reported to date. Taken together, this study constructed a B. licheniformis strain BL10/PykzA-P43-SPSacC-ansZ capable of efficiently producing L-asparaginase, which laid the foundation for industrial production of L-asparaginase.

Metabolic engineering of L-cysteine supply modules for enhanced production of bacitracin in Bacillus licheniformis / 生物工程学报

Bacitracin is a broad-spectrum antibiotics mainly produced by Bacillus, and is used as veterinary medicine in the fields of livestock and poultry breeding. Insufficient supply of precursor amino acids might be an important factor that hinders high-level microbial production of bacitracin. We investigated the effect of strengthening L-cysteine supply on bacitracin production by an industrial bacitracin producer, Bacillus licheniformis DW2. Overexpression of cysK encoding L-cysteine synthase led to a 9.17% increase of the bacitracin titer. Moreover, overexpression of cysE encoding L-serine acetyltransferase and cysP encoding thiosulfate/sulfate intracellular transporter increased the bacitracin titers by 7.23% and 8.52%, respectively. Moreover, overexpression of a putative cystine importer TcyP led to a 29.19% increase of intracellular L-cysteine, and bacitracin titer was increased by 7.79%. Subsequently, the strong promoter PbacA was used to replace the promoters of genes cysP, cysE and tcyP in strain DW2::ysK, respectively. The resulted strain CYS4 (DW2::cysK-PbacA-(cysP)-PbacA(cysE)- PbacA(tcyP) produced 910.02 U/mL bacitracin, which was 21.10% higher than that of the original strain DW2 (747.71 U/mL). Together with the experiments in 3 L fermenters, this research demonstrated that enhancing intracellular L-cysteine supply is an effective strategy to increase bacitracin production of B. licheniformis.

Isolation, identification and prokaryotic expression of a bacteriocin-like substance from Bacillus licheniformis / 生物工程学报

The ban on addition of antibiotics in animal feed in China has made the search for new antibiotics substitutes, e.g. bacteriocin, a hot topic in research. The present study successfully isolated an antibacterial substance producing strain of Bacillus sp. from alpaca feces by agar diffusion method, using Escherichia coli, Salmonella enterica, Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus and Listeria monocytogenes as indicator bacteria. The isolated strain was named as B. licheniformis SXAU06 based on colony morphology, Gram staining and 16S rRNA gene sequence. The antibacterial substance was isolated and purified through a series of procedures including (NH4)2SO4 precipitation, chloroform extraction, molecular interception and SDS-PAGE analysis. Bioinformatics analysis of the LC-MS/MS data indicated that the antibacterial substance was a bacteriocin-like substance (BLIS) with an approximate molecular weight of 14 kDa, and it was designated as BLIS_SXAU06. BLIS_SXAU06 exhibited high resistance to treatment of proteinase K, high temperature, high acidity and alkalinity. BLIS_SXAU06 was heterologously expressed in E. coli and the recombinant BLIS_SXAU06 exhibited effective antibacterial activity against S. aureus, S. epidermidis, M. luteus, and L. monocytogenes, showing potential to be investigated further.

Improving the yield of Anoectochilus roxburghii by Bacillus licheniformis cultured in Agaricus bisporus industrial wastewater

BACKGROUND: There is a large amount of industrial wastewater produced by the mushroom industry during the canning processing each year, which could provide abundant carbon, nitrogen and inorganic salts for microbial growth. The aim of this study was to optimize the culture conditions for Bacillus licheniformis cultured in the Agaricus bisporus industrial wastewater to produce the agricultural microbial fertilizer. RESULTS: In this work, the maximal biomass of B. licheniformis could be obtained under the following culture conditions: 33.7°C, pH 7.0, 221 rpm shaking speed, 0.5% wastewater, 2 (v:v, %) inoculum dose, loading liquid of 60 mL/250 mL and a culture time of 24 h, and the average experimental value obtained was 1.35 ± 0.04 × 109 Obj/mL, which was within the 95% confidence interval of the predicted model (1.29­1.38 × 109 Obj/mL), and met the national microbial fertilizers' standard in China. Furthermore, the field experiment results showed that the fermentation broth of B. licheniformis could significantly improve the yield of Anoectochilus roxburghii. CONCLUSIONS: Agaricus bisporus industrial wastewater can be used to produce agricultural microbial fertilizer.

Enhanced production of bacitracin via energy metabolism engineering in Bacillus licheniformis DW2 / 生物工程学报

Bacitracin is a broad-spectrum cyclic peptide antibiotic, and mainly produced by Bacillus. Energy metabolism plays as a critical role in high-level production of target metabolites. In this study, Bacillus licheniformis DW2, an industrial strain for bacitracin production, was served as the original strain. First, our results confirmed that elimination of cytochrome bd oxidase branch via deleting gene cydB benefited bacitracin synthesis. Bacitracin titer and ATP content were increased by 10.97% and 22.96%, compared with those of original strain, respectively. Then, strengthening cytochrome aa3 oxidase branch via overexpressing gene qoxA was conducive to bacitracin production. Bacitracin titer and ATP content were increased by 18.97% and 34.00%, respectively. In addition, strengthening ADP synthesis supply is also proven as an effective strategy to promote intracellular ATP accumulation, overexpression of adenosine kinase DcK and adenylate kinase AdK could all improve bacitracin titers, among which, dck overexpression strain showed the better performance, and bacitracin titer was increased by 16.78%. Based on the above individual methods, a method of combining the deletion of gene cydB and overexpression of genes qoxA, dck were used to enhance ATP content of cells to 39.54 nmol/L, increased by 49.32% compared to original strain, and bacitracin titer produced by the final strain DW2-CQD (DW2ΔcydB::qoxA::dck) was 954.25 U/mL, increased by 21.66%. The bacitracin titer produced per cell was 2.11 U/CFU, increased by 11.05%. Collectively, this study demonstrates that improving ATP content was an efficient strategy to improve bacitracin production, and a promising strain B. licheniformis DW2-CQD was attained for industrial production of bacitracin.

Twin-arginine signal peptide of Bacillus licheniformis GlmU efficiently mediated secretory expression of protein glutaminase

Background: Protein glutaminase specifically deamidates glutamine residue in protein and therefore significantly improves protein solubility and colloidal stability of protein solution. In order to improve its preparation efficiency, we exploited the possibility for its secretory expression mediated by twin-arginine translocation (Tat) pathway in Bacillus licheniformis. Results: The B. licheniformis genome-wide twin-arginine signal peptides were analyzed. Of which, eleven candidates were cloned for construction of expression vectors to mediate the expression of Chryseobacterium proteolyticum protein glutaminase (PGA). The signal peptide of GlmU was confirmed that it significantly mediated PGA secretion into media with the maximum activity of 0.16 U/ml in Bacillus subtilis WB600. A mutant GlmU-R, being replaced the third residue aspartic acid of GlmU twin-arginine signal peptide with arginine by site-directed mutagenesis, mediated the improved secretion of PGA with about 40% increased (0.23 U/ml). In B. licheniformis CBBD302, GlmU-R mediated PGA expression in active form with the maximum yield of 6.8 U/ml in a 25-l bioreactor. Conclusions: PGA can be produced and secreted efficiently in active form via Tat pathway of B. licheniformis, an alternative expression system for the industrial-scale production of PGA.

Development and verification of an FLP/FRT system for gene editing in Bacillus licheniformis / 生物工程学报

Few tools of gene editing have been developed in Bacillus licheniformis at present. In order to enrich the tools, an FLP/FRT gene editing system that can repeatedly use a single selectable marker was constructed in Bacillus licheniformis, and the system was verified by knocking out an alpha amylase gene (amyL), an protease gene (aprE) and knocking in an exogenous Vitreoscilla hemoglobin gene (vgb). First, knock-out plasmids pNZTT-AFKF of amyL and pNZTT-EFKF of aprE were constructed using thermosensitive plasmid pNZT1 as a carrier. The two knock-out plasmids contained respective homology arms, resistance genes and FRT sites. Then the knock-out plasmids were transformed into Bacillus licheniformis and the target genes were replaced by respective deletion cassette via twice homologous exchange. Finally, an expression plasmid containing FLP recombinase reading frane was introduced and mediated the excision of resistance marker. In order to expand the practicability of the system, knock-in plasmid pNZTK-PFTF-vgb was constructed, with which knock-in of vgb at pflB site was carried out successfully. The results showed that amyL and aprE were successfully knocked out and the marker kanamycin cassette exactly excised. The activities of amylase and protease of deletion mutants were reduced by 95.3% and 80.4% respectively. vgb was successfully knocked in at pflB site and the marker tetracycline cassette excised. The expression of integrated vgb was verified via real-time PCR. It is the first time to construct an FLP/FRT system for gene editing in Bacillus licheniformis, which could provide an effective technical means for genetic modification.

Isolation and Identification of Novel IndigenousBacterial Strain as a Low Cost Pectinase Source

ABSTRACT The present study was concerned with the searching of novel bacterial cultures from different samples for the lab scale production of pectinase. Keeping in view the increasing demand of pectinase specially in Faisalabad, an industrial city of Pakistan, isolation of new hyper producer bacterial strains locally is an easy and cheap way of getting the desirable products at low cost. Therefore, isolation of new strains for industrial enzyme production has been and will be remained a part of research every time. This method alone can also provide raw material for further research such as enzyme engineering or molecular directed evolution. For the identification of hyper producer strain colony PCR was done for 16S rRNA analysis. Reason to use the 16S rRNA for identification purpose is that the gene is fairly short and can be amplified quickly and easily. The bacterial isolate (sources of pectinase enzyme) was identified based on PCR amplification of 16S rRNA and for this purpose the amplified product was run in agarose gel against a known species of Bacillus licheniformis. The 16S rRNA sequencing confirmed the Bacillus status of the strain.

Enhanced production of bacitracin by knocking out of amino acid permease gene yhdG in Bacillus licheniformis DW2 / 生物工程学报

Bacitracin is a broad-spectrum polypeptide antibiotic, which is formed by 11 amino acids residues. Precursor amino acids supply might be the limit factor during bacitracin fermentation. First, our results demonstrated that increasing Ile and Leu supplies were regarded as the efficient strategies for the enhanced titer of bacitracin. Then, the amino acid permease YhdG, which was identified as the BCAA permease, was deleted and overexpressed in DW2, respectively. Our results showed that knocking out of permease YhdG could improve bacitracin production remarkablely. The bacitracin titer of the yhdG deficient strain DW2ΔyhdG reached 917.35 U/mL by flask fermentation, increased by 11% compared with that of DW2. In addition, the bacitracin titer was decreased by 25% in the YhdG overexpressed strain. Meanwhile, the intracellular concentrations of BCAA were higher than DW2 during the biosynthesis of bacitracin. The above results suggested that the permease YhdG might act as an exporter for branched chain amino acids in B. licheniformis DW2. Taken together, the increasing intracellular concentrations of branched chain amino acids by deleting amino acid permease YhdG could improve bacitracin titer. This study provided a new strategy for high-level production of bacitracin.

Combined strategies for improving production of a thermo-alkali stable laccase in Pichia pastoris

Background: Laccases are copper-containing enzymes which have been used as green biocatalysts for many industrial processes. Although bacterial laccases have high stabilities which facilitate their application under harsh conditions, their activities and production yields are usually very low. In this work, we attempt to use a combinatorial strategy, including site-directed mutagenesis, codon and cultivation optimization, for improving the productivity of a thermo-alkali stable bacterial laccase in Pichia pastoris. Results: A D500G mutant of Bacillus licheniformis LS04 laccase, which was constructed by site-directed mutagenesis, demonstrated 2.1-fold higher activity when expressed in P. pastoris. The D500G variant retained similar catalytic characteristics to the wild-type laccase, and could efficiently decolorize synthetic dyes at alkaline conditions. Various cultivation factors such as medium components, pH and temperature were investigated for their effects on laccase expression. After cultivation optimization, a laccase activity of 347 ± 7 U/L was finally achieved for D500G after 3 d of induction, which was about 9.3 times higher than that of wild-type enzyme. The protein yield under the optimized conditions was about 59 mg/L for D500G. Conclusions: The productivity of the thermo-alkali stable laccase from B. licheniformis expressed in P. pastoris was significantly improved through the combination of site-directed mutagenesis and optimization of the cultivation process. The mutant enzyme retains good stability under high temperature and alkaline conditions, and is a good candidate for industrial application in dye decolorization.

Highly efficient enzymatic preparation of isomalto-oligosaccharides from starch using an enzyme cocktail

Background: Current commercial production of isomalto-oligosaccharides (IMOs) commonly involves a lengthy multistage process with low yields. Results: To improve the process efficiency for production of IMOs, we developed a simple and efficient method by using enzyme cocktails composed of the recombinant Bacillus naganoensis pullulanase produced by Bacillus licheniformis, α-amylase from Bacillus amyloliquefaciens, barley bran ß-amylase, and α-transglucosidase from Aspergillus niger to perform simultaneous saccharification and transglycosylation to process the liquefied starch. After 13 h of reacting time, 49.09% IMOs (calculated from the total amount of isomaltose, isomaltotriose, and panose) were produced. Conclusions: Our method of using an enzyme cocktail for the efficient production of IMOs offers an attractive alternative to the process presently in use.

One Factor at A Time based optimization of protease from poultry associated Bacillus licheniformis.

Bacteria were isolated from poultry farm of Guduvanchery, Tamil Nadu, India and exhibited variable protease activity on skim milk agar plates. Of 10 bacterial isolates screened, Bacillus licheniformis strain 018 was observed as a hyperprotease producer and it was further characterized using biochemical and molecular tools. Protease production from the isolate was enhanced by optimizing the culture conditions using One Factor at A Time (OFAT) method. The bacteria exhibited its optimal enzyme activity at pH- 9.0, temperature- 35⁰C, agitation speed- 130 rpm, incubation time- 24 h, carbon source- casein and nitrogen source- yeast extract. On the other hand, the crude proteases were found to be significantly active and stable at broad range of pH (5.0-9.0) and temperature (30-60⁰C). To the best of my knowledge this is the first report on the production and enhancement of alkaline protease from poultry farm isolate using OFAT method. Stability of the enzyme at high temperature and pH can be explored for varied industrial applications.

Efficacy and safety of Bifidobacterium tetravaccine tablets in the treatment of persistent and chronic diarrhea: a randomized controlled clinical study / 中华消化杂志

Objective To compare the differences in the efficacy of Bifidobacterium tetravaccine tablets.Bifidobacterium triple viable capsules and live Bacillus licheniformis capsule in the treatment of persistent and chronic diarrhea.Methods From September 2015 to June 2016,a total of 484 outpatients with persistent and chronic diarrhea were enrolled and divided into observation group (treated with Bifidobacterium tetravaccine tablets) and control group (treated with the combination of Bifidobacterium triple viable capsules and live Bacillus licheniformis capsule).Before and after treatment,the frequency of defecation and the characters of stool were observed and the differences in the treatment efficacy in persistent and chronic diarrhea between two groups were compared.Paired t test and Chi square test were used to compare the difference before and after treatment in each group,and independent sample t test was used for comparison between groups.Results There were a total of 256 patients in the observation group (four cases lost and 256 cases were completed).Meanwhile there were 228 patients in the control group (30 cases lost and 228 cases completed).In the observation group,after treatment the frequency of defecation was (2.13±1.06) times,which was less than that before treatment ((3.83±0.95) times),and the difference was statistically significant (t=29.149,P＜0.01).In the control group,after treatment the frequency of defecation was (2.19 ± 1.06) times,which was less than that before treatment ((3.87 ±0.98) times),and the difference was statistically significant(t =27.800,P＜0.01).There was no statistically significant difference in the frequency of defecation before and after treatment between two groups (t=-0.460 and-0.662,both P＞0.05).Furthermore there was also no statistically significant difference in the rate of normal bowel movements between observation group and treatment group after treatment (50.8％(130/256) vs 57.9％(132/228;x2=2.458,P=0.117).There was no significant difference in effective rate (64.8％(166/256) vs 69.7％ (159/228) and excellence rate (47.7％ (122/256) vs 51.3％ (117/228)) between two groups (P=0.253 and 0.422);besides,no severe adverse events were reported.Conclusion In the aspect of improving of times of defecation and characters of stool in patients with persistent and chronic diarrhea,single medication of multi bacteria strains Bifidobacterium tetravaccine tablets has the same satisfied efficacy and good safety as the combination of Bifidobacterium triple viable capsules and live Bacillus licheniformis capsule.

Keratinolytic Protease Production and Characterization from Bacillus Sp. Isolated from Poultry Wastes.

Keratinases originating from microorganisms are used in many industrial fields such as the recycle of keratinous wastes, leather, textile, the detergent industry and medical applications. In this study, 42 Bacillus strain were isolated from Cukurova University Research and Application and Chicken Management Unit. 8 of these isolates showed proteolytic activity on skim-milk and keratinolytic activity with keratin-azure on the basal feather-meal medium. Strain H62 with the highest keratinase activity was determined as the keratinase producer and identified as Bacillus licheniformis with microscopic, biochemical (VITEK-2, 90%) and molecular analysis (16S rRNA, 99%, B. licheniformis 9945A). The highest enzyme production was carried out at 40°C for 45 hours by adding 0.1 g/l mannitol (as carbon source), 0.1 g/l ammonium nitrate (as nitrogen source) and 15 g/l feathermeal into the basal feather-meal medium. Although keratinase showed the activity at 20-90°C and pH 5.0-13.0, optimum activity was obtained at 40°C and pH 9.5. 100% of stability was determined at pH 8.0, whereas the loss of activity was observed at pH 7.0-9.0. After a pre-incubation at 20-100°C enzyme was 100% stable whereas activity was decreased at the other temperatures. At room temperature, a loss of activity was determined after the 24th hour. EDTA, SDS and Urea increased the enzyme activity; however, Tween-20 was decreased. The enzyme was seen to be a single band with a molecular weight of 26 kDa. As a result, keratinase B. Licheniformis H62 is an enzyme that can be used in mesophyll and alkaline conditions, particularly in medical applications and as feed supplements.

Optimization of Media Constituents for the Production of Alkaline Protease from Bacillus Licheniformis.

Production of alkaline protease by Bacillus licheniformis has been investigated under submerged fermentation. The physical and chemical parameters influencing submerged fermentation were optimized. The effect of incubation time, temperature, pH, carbon sources and nitrogen sources and additional nutrients on the production of alkaline protease was characterized. The optimum conditions for the protease production by Bacillus licheniformis were found to be at pH 9.0 and temperature at 40ºC. The outcome of carbon and inorganic nitrogen sources on protease production proved that glucose and casein were the effective medium ingredients for Bacillus licheniformis respectively. The maximum amount of protease production was recorded in medium supplemented with ammonium sulphate. Among the tested metal ions, the level of protease yield was found to be high in medium supplemented with magnesium chloride. The protease production was amplified in the presence of 1.5% sodium chloride. The extreme stability towards Triton X-100, Tween 20 and SDS was observed in Bacillus licheniformis alkaline protease.

Occurrence and characterization of toxigenic Bacillus cereus in food and infant feces

Objective: To investigate the true incidence of Bacillus cereus (B. cereus) in food and children diarrhea cases. Methods: A total of 110 samples of various dairy products such as raw milk, long life pasteurized milk, yoghurt and infant powdered milk formulas, raw rice, and feces were examined for the presence of B. cereus by selective plating on mannitol-egg-yolkpolymyxin agar. Confirmation of B. cereus was carried out by biochemical tests and PCR. Identification of non-B. cereus isolates was carried out by 16S rDNA sequencing. Antimicrobial susceptibility was done by disk diffusion method. Results: Overall 35 samples (31.8%, n = 110) yielded Bacillus-like growth. Of which 19 samples (54.28%) were positive for B. cereus. All isolates were positive for enterotoxin production. No psychrotolerant B. cereus strains were detected in all samples. All B. cereus isolates were resistant to penicillin G, but susceptible to vancomycin, erythromycin and clindamycin. Conclusions: The results of this study confirm the importance of including B. cereus in disease control and prevention programs, as well as in routine clinical and food quality control laboratories in both Saudi Arabia and Egypt.

Occurrence and characterization of toxigenic Bacillus cereus in food and infant feces

Objective:To investigate the true incidence of Bacillus cereus (B. cereus) in food and children diarrhea cases. Methods:A total of 110 samples of various dairy products such as raw milk, long life pasteurized milk, yoghurt and infant powdered milk formulas, raw rice, and feces were examined for the presence of B. cereus by selective plating on mannitol-egg-yolk-polymyxin agar. Confirmation of B. cereus was carried out by biochemical tests and PCR. Identification of non-B. cereus isolates was carried out by 16S rDNA sequencing. Antimicrobial susceptibility was done by disk diffusion method. Results:Overall 35 samples (31.8%, n=110) yielded Bacillus-like growth. Of which 19 samples (54.28%) were positive for B. cereus. All isolates were positive for enterotoxin production. No psychrotolerant B. cereus strains were detected in all samples. All B. cereus isolates were resistant to penicillin G, but susceptible to vancomycin, erythromycin and clindamycin. Conclusions:The results of this study confirm the importance of including B. cereus in disease control and prevention programs, as well as in routine clinical and food quality control laboratories in both Saudi Arabia and Egypt.

Comparative efficacy and mechanism of monotherapy and combination therapy of Bacillus licheniformis in mice with acute ulcerative colitis / 中国药学杂志

OBJECTIVE: To investigate the therapeutic efficacy of treatment of Bacillus licheniformis (BL) on ulcerative colitis(UC) in BALB/c mice. METHODS: The therapeutic effect of different treatment was evaluated in seven acute UC mice groups and one control group, including the normal group, the model group, the solvent group, the sulfasalazine (SASP) treated group, the high dose BL treated group, the low dose BL treated group, the high dose BL with SASP treated group and the low dose BL with SASP treated group. The disease activity index (DAI) score of mice were recorded every other day since the experiment started. On the 15th day, all the mice were killed, then gross injury score in colonic mucosa and histopathological changes were measured. The expression levels of NF-κB and Bcl-2 in mouse colonic mucosa was also determined by immunohistochemistry method. RESULTS: The DAI score, the colonic gross injury score, the histopathological changes and the expression level of NF-κB and Bcl-2 of mice colonic mucosa in drug treated groups were decreased significantly when comparing with the drug untreated groups. Moreover, these results were even better in two drugs combined treated groups than in single drug treated groups (P<0.05). CONCLUSION: BL has the efficacy of remission DSS-induced acute ulcerative colitis in mice, and there is more effective when it is administered with SASP. The results indicat that the therapeutic effort is via inhibiting the expression of NF-κB and Bcl-2 in colonic mucosa.

A Double-Blind, Randomized, Active Drug Comparative, Parallel-Group, Multi-Center Clinical Study to Evaluate the Safety and Efficacy of Probiotics (Bacillus licheniformis, Zhengchangsheng(R) capsule) in Patients with Diarrhea

BACKGROUND/AIMS: Bacillus Licheniformis, a probiotic used in the treatment of diarrhea, has been shown to suppress the growth of pathologic bacteria. This study was performed to assess the therapeutic efficacy and safety of Zhengchangsheng(R) (Bacillus Licheniformis) in comparison with another probiotic, Bioflor(R) (Saccharomyces Boulardii) for the treatment of diarrhea. METHODS: Patients with diarrhea (n=158) were randomized to receive Zhengchangsheng(R) or Bioflor(R) for 5 days. The existence or non-existence of formed feces, changes in daily stool frequency, improvement of subjective symptoms, and changes in the severity of diarrhea were compared. RESULTS: Of the 158 full analysis set (FAS) patient population, 151 patients comprised the per protocol (PP) analysis. The rates of recovered to formed feces in the Bacillus and Saccharomyces groups were 91.0% vs. 95.0% in the FAS (P=0.326) and 90.5% vs. 96.1% in the PP analysis (P=0.169), respectively. The mean duration of diarrhea changing to formed feces was 3.15+/-1.10 days in the Bacillus group and 3.22+/-1.01 in the Saccharomyces group (P=0.695, FAS). The frequency of defecation, subjective symptoms, and degree of severe diarrhea were improved in both groups, however, there were no statistically significant differences between the 2 groups. Analysis of the 95% confidence intervals for the differences in the rate of recovery to formed feces between the 2 groups met the criteria for non-inferiority of Bacillus compared to Saccharomyces. No significant adverse events were observed during the study period. CONCLUSIONS: Zhengchangsheng(R) is not inferior to Bioflor(R) in therapeutic efficacy and is a safe and useful therapeutic agent for the treatment of diarrhea.

Isolation and Identification of Xylanolytic Enzyme from an Effective Strain Bacillus Licheniformis Isolated from the Decaying Wood.

A new species of Bacillus licheniformis produced extracellular xylanase under submerged fermentation when wheat bran is used as carbon source. The xylan is the most common hemicellulosic polysaccharide in food industry and agricultural wastes, comprising a backbone of xylose residues linked by β-1,4 glycosidic bonds. Bacillus licheniformis has been shown to be a promising organism for enhanced production of xylanases & β-xylosidase under submerged fermentation (SmF). The optimization of cultural conditions and carbon, nitrogen sources for enzymes production. The bacterial strain Bacillus licheniformis was cultivated using as substrate xylan, wheat bran, corn straw, corncob, and sugarcane bagasse. Wheat bran has been a good xylanase (16.8U/ml) & β xylosidase (5.6U/ml) activity after 48h of fermentation. Maximum enzyme activity was observed in xylan as carbon source and peptone as nitrogen source. Both crude enzymes were characterized and a bacterial xylanase shows optimum pH for xylanase activity at 6.5 & β xylosidase were found to be 6.0. The optimum temperatures were 450C for both and they were thermally stable up to 500C. The parameters of Vmax and Km obtained using Line weaver-Burk plot method were 277.7μmol / min/mg and 5.26 mg /L correspondingly.