Extracellular Xylanopectinolytic Enzymes by Bacillus subtilis ADI1 from EFB's Compost

Effect of Fermentation Response on Biosynthesis of Endopolygalacturonase from a Potent Strain of Bacillus by Utilizing Polymeric Substrates of Agricultural Origin

Endopolygalacturonase (EndoPGase), EC: 3.2.1.15. is one of the crucial pectinases belonging to the class of carbohydrase. The catalytic action of EndoPGase captivates the attention of the production of this extremely valuable catalyst in the industrial sector. The main focus was to ascertain a potential bacterial candidate for endoPGase production. The isolated bacterial strain was further identified by 16S rRNA gene sequencing. The parameters for enzyme biosynthesis were optimized by a single and multiple factor approach at a time. The results of our investigation led to the identification of a potent strain of Bacillus subtilis NR2 [strain 168]. The sequence of 16S rRNA amplified from the isolated bacterium has been submitted to GenBank under accession number ON738697. The strain was found active for pectic enzyme activity under shaking- flask fermentation at pH 5.0 and 50 °C temperature of incubation. Among all monomeric and polymeric substrates (inducer-substrates), citrus pectin, followed by potato starch and pectin (Sigma) were considered the best enzyme inducers at 1% concentration. In comparison, an increased wheat bran concentration at 5% was proved to be ideal for EndoPGase biosynthesis Moreover, an increasing trend in enzyme activity was observed with the increasing concentration of inducer. The combined effect of three variables (pH, inducer-substrates, and inducer-substrate concentration) was explored by response surface methodology (RSM) involving a Box–Behnken design (BBD). Based on the results, we concluded that the soil-isolated B. subtilis can be effectively utilized for commercial-scale pectinase enzyme biosynthesis.

Production, statistical optimization, and functional characterization of alkali stable pectate lyase of Paenibacillus lactis PKC5 for use in juice clarification

Pectate lyase is a hydrolytic enzyme used by diverse industries to clarify food. The enzyme occupies a 25% share of the total enzyme used in food industries, and their demand is increasing gradually. Most of the enzymes in the market belong to the fungal origin and take more time to produce with high viscosity in the fermentation medium, limiting its use. The bacteria belonging to the genus Bacillus have vast potential to produce diverse metabolites of industrial importance. The present experiment aimed to isolate pectate lyase-producing bacteria that can tolerate an alkaline environment at moderate temperatures. Bacillus subtilis PKC2, Bacillus licheniformis PKC4, Paenibacillus lactis PKC5, and Bacillus sonorensis ADCN produced pectate lyase. The Paenibacillus lactis PKC5 gave the highest protein at 48 h of incubation that was partially purified using 80% acetone and ammonium sulphate. Purification with 80% acetone resulted in a good enzyme yield with higher activity. SDS-PAGE revealed the presence of 44 kDa molecular weight of purified enzyme. The purified enzyme exhibits stability at diverse temperature and pH ranges, the maximum at 50 °C and 8.0 pH. The metal ions such as Mg2+, Zn2+, Fe2+, and Co2+ significantly positively affect enzyme activity, while increasing the metal ion concentration to 5 mM showed detrimental effects on the enzyme activity. The organic solvents such as methanol and chloroform at 25% final concentration improved the enzyme activity. On the other hand, detergent showed inhibitory effects at 0.05% and 1% concentration. Pectate lyase from Paenibacillus lactis PKC5 had Km and Vmax values as 8.90 mg/ml and 4.578 μmol/ml/min. The Plackett–Burman and CCD designs were used to identify the significant process parameters, and optimum concentrations were found to be pectin (5 gm%) and ammonium sulphate (0.3 gm%). During incubation with pectate lyase, the clarity percentage of the grape juice, apple juice, and orange juice was 60.37%, 59.36%, and 49.91%, respectively.

Xylanolytic enzyme consortia from Bacillus sp. NIORKP76 for improved biobleaching of kraft pulp

A cellulase-free xylanolytic enzyme consortia consisting of a xylanase, arabinofuranosidase, and acetyl xylan esterase produced by Bacillus sp. NIORKP76 isolate under solid-state fermentation was assessed for its bio-bleaching ability on kraft pulp. In the biobleaching analysis, the xylanase dose of 5 Ug^-1 dry pulp denoted the optimum bleaching of pulp at 40 °C and pH 8.0 after 2 h of treatment. The reduction in kappa number of pre-treated hardwood pulp using xylanolytic enzyme consortium (XEC) was found to be ~ 55%, while solo xylanase could reduce the kappa number to 44-46%. In the case of chemical bagasse pulp, a reduction of ~ 27.5% and 19-20% was seen in kappa number using XEC and solo xylanase, respectively. Enzyme-treated pulp (HW and CB) showed a 50% reduction in hypochlorite consumption during the chlorine treatment. The current study results reveal the significant potential of xylanolytic enzyme consortium from Bacillus sp. NIORKP76 on the environmentally friendly bio-bleaching process.

Evaluation of the Antimicrobial and Anti-inflammatory Properties of Bacillus-DFM (Norum™) in Broiler Chickens Infected With Salmonella Enteritidis

Restrictions of in-feed antibiotics use in poultry has pushed research toward finding appropriate alternatives such as Direct-Fed Microbials (DFM). In this study, previously tested Bacillus isolates (B. subtilis and B. amyloliquefaciens) were used to evaluate their therapeutic and prophylactic effects against Salmonella enterica serovar Enteritidis (S. Enteritidis) in broiler chickens. For this purpose, initial antibacterial activity of Bacillus-DFM (10⁴ spores/g or 10⁶ spores/g) against S. Enteritidis colonization in crop, proventriculus and intestine was investigated using an in vitro digestive model. Furthermore, to evaluate therapeutic and prophylactic effects of Bacillus-DFM (10⁴ spores/g) against S. Enteritidis colonization, altogether 60 (n = 30/group) and 30 (n = 15/group) 1-day-old broiler chickens were randomly allocated to either DFM or control group (without Bacillus-DFM), respectively. Chickens were orally gavaged with 10⁴ cfu of S. Enteritidis per chicken at 1-day old, and cecal tonsils (CT) and crop were collected 3 and 10 days later during the therapeutic study, whereas they were orally gavaged with 10⁷ cfu of S. Enteritidis per chicken at 6-day-old, and CT and crop were collected 24 h later from two independent trials during the prophylactic study. Serum superoxide dismutase (SOD), FITC-d and intestinal IgA levels were reported for both chicken studies, in addition cecal microbiota analysis was performed during the therapeutic study. DFM significantly reduced S. Enteritidis concentration in the intestine compartment, and in both proventriculus and intestine compartments as compared to the control when used at 10⁴ spores/g and 10⁶ spores/g, respectively (p < 0.05). DFM significantly reduced FITC-d and IgA as well as SOD and IgA levels (p < 0.05) compared to the control in therapeutic and prophylactic studies, respectively. Interestingly, in the therapeutic study, there were significant differences in bacterial community structure and predicted metabolic pathways between DFM and control. Likewise, phylum Actinobacteria and the genera Bifidobacterium, Roseburia, Proteus, and cc_115 were decreased, while the genus Streptococcus was enriched significantly in the DFM group as compared to the control (MetagenomeSeq, p < 0.05). Thus, the overall results suggest that the Bacillus-DFM can reduce S. Enteritidis colonization and improve the intestinal health in chickens through mechanism(s) that might involve the modulation of gut microbiota and their metabolic pathways.

Extracellular Pectinase from a Novel Bacterium Chryseobacterium indologenes Strain SD and Its Application in Fruit Juice Clarification

Pectinase is one of the important enzymes of industrial sectors. Presently, most of the pectinases are of plant origin but there are only a few reports on bacterial pectinases. The aim of the present study was to isolate a novel and potential pectinase producing bacterium as well as optimization of its various parameters for maximum enzyme production. A total of forty bacterial isolates were isolated from vegetable dump waste soil using standard plate count methods. Primary screening was done by hydrolysis of pectin. Pectinase activity was determined by measuring the increase in reducing sugar formed by the enzymatic hydrolysis of pectin. Among the bacterial isolates, the isolate K6 exhibited higher pectinase activity in broth medium and was selected for further studies. The selected bacterial isolate K6 was identified as Chryseobacterium indologenes strain SD. The isolate was found to produce maximum pectinase at 37°C with pH 7.5 upon incubation for 72 hours, while cultured in production medium containing citrus pectin and yeast extract as C and N sources, respectively. During enzyme-substrate reaction phase, the enzyme exhibited its best activity at pH of 8.0 and temperature of 40°C using citrus pectin as substrate. The pectinase of the isolate showed potentiality on different types of fruit juice clarification.