Starch Hydrolysis Test Research Articles

Genus Pseudonocardia: What we know about its biological properties, abilities and current application in biotechnology.

The genus Pseudonocardia belongs to a group of Actinomycetes, and is a member of the family Pseudonocardiacea. The members of this genus are aerobic, Gram-positive, non-motile bacteria that are commonly found in soil, plant and environment. Although this genus has a low clinical significance; however, it has an important role in biotechnology due to the production of secondary metabolites, some of which have anti-bacterial, anti-fungal and anti-tumour effects. The use of phenotypic tests, such as gelatinase activity, starch hydrolysis, catalase and oxidase tests, as well as molecular methods, such as polymerase chain reaction, are necessary for Pseudonocardia identification at the genus and species levels.

Studies on cultural, morphological and biochemical characterization of Bradyrhizobium japonicum of soybean

Soybean (Glycine max L. Merrill), being a leguminous crop, can be fix atmospheric nitrogen through symbiotic association with effective and competitive strains of Rhizobia (Bradyrhizobium japonicum/Rhizobium japonicum) and thereby improve soil fertility as well as productivity of subsequent cereal crops. Bradyrhizobium japonicum was isolated from root nodules of Soybean (Glycine max L.) on Congo-Red Yeast Extract Mannitol Agar (CR-YEMA) medium and its morphological, cultural and biochemical-characteristics were studied. The test bacterium was circular, convex, glistening, whitish pink colonies (0-4 mm dia.) with entire margin. The bacterium was Gram-negative, non-spore forming and motile rods and showed positive reactions to Catalase oxidation, Potassium hydroxide test, and Starch hydrolysis tests.

Description of isolated bacterial pathogens from diseased Cirrhinus mrigala

The purpose of this study was to isolate and characterize the disease causative bacterial species from commercially important freshwater fish species, Cirrhinus mrigala. For this purpose, diseased C. mrigala samples were collected both from cultured and wild conditions. From sampled fish, extracted gills, liver, intestine and skin were homogenized in PBS buffer. Bacterial isolation was achieved by inoculating samples on nutrient agar plates using the method of pour plate and streak plate. Maximum total bacterial load was found 3.4 × 105. Bacterial isolates were identified using morphological, physiological and biochemical features. Gram stain, motility, catalase, starch hydrolysis, fermentation, Indole, Methyl red, Voges-Proskauer and Urease tests were performed for identification. In short, isolated bacteria were identified as Escherichia coli, Staphylococcus aureus, Bacillus cereus and Citrobacter freundii. Pathogenicity was confirmed in healthy fish by the use of reproduced isolate through experimental infection to fulfil Koch's postulates. Variations in organ structures were studied by histopathology and changes that were found to be lesions, tissue degenerations, necrotic and haemorrhages. This study will be supportive in formulating control measures for disease prevention and successful treatment for these pathogenic bacteria.

BIOREMEDIATION OF CRUDE OIL CONTAMINATED SOIL BY HYDROCARBON DEGRADING BACTERIA

Proficiency of hydrocarbon-degrading bacteria useful for eradicating soil pollution stimulated by seepage of petroleum and their derivative substances, therefore, sequestered different bacterial isolates were bear significant merits for utilizing hydrocarbons as an uncommon source of their growth and development. A colorimetric assay was performed at 595 nm wavelength which was subjected to the mineral salt broth with 1% oil (petrol, diesel, and burned out engine oil). This broth having minimum nutrients used by inoculated bacteria in which some isolates were adopted for taking a sufficient amount of either petrol, diesel, or burned-out engine oil as carbon source hence increases its turbidity that was measured in two days time interval up to twelve days of observation. We found that selected isolates were able to degrade burned out engine oil efficiently in contrast to petrol and diesel. At optical density 0.21± 0.13, 0.19±0.08, 0.18±0.09, 0.17±0.12 the result showed by isolatesBI-7, BI-2, BI-4, BI-6goodcompetency to degrade burned out engine oil. On the other hand, maximum diesel and petrol utilized by BI-2 & BI-1 isolate at O.D. 0.09±0.02, 0.05±0.02 was recorded. Most of the bacterial isolates resulted in a positive biochemical test. BI-1 & BI-7 resulted in positive starch hydrolysis test, whereas, all isolates resulted in positive urease test, simultaneously negative results for all isolates obtained when catalase and antibiotic sensitivity test against streptomycin were performed.

Isolation and characterization of rhizospheric microorganisms from bacterial wilt endemic areas in Kenya

Ralstonia solanacearum is a soil-borne bacterium causing bacterial wilt, particularly in Solanaceae crops, including tomatoes. Due to pathogen’s wide host plant range, pesticide resistance, and ability to overcome cultivars utilized for innate resistance, not even a single measure is effective against the pathogen. Screening the rhizosphere of bacterial wilt tolerant tomato plants from Bomet, Kiambu, Kajiado and Kirinyaga regions of Kenya for beneficial bacterial and fungal isolates was done using nutrient agar and potato dextrose agar, respectively. Morphological, biochemical, and microscopic characterization to identify the genus of fungal and microbial isolates revealed a total of 41 bacterial and 42 fungal isolates distributed as Bomet>Kiambu>Kajiado>kirinyaga while fungal isolates were as Bomet>Kiambu>Kirinyaga>Kajiado. Methyl Red (MR) and Voges-Proskauer (VP) tests, catalase reaction, citrate reaction, starch hydrolysis, and triple iron sugar (TSI) tests showed that the predominant bacteria were Burkholderia, Bacillus and Micrococcus species. Pseudomonas, Streptomyces, Serratia, and Enterobacter species were the least. Aspergillus, Trichoderma, and Fusarium species were the most dominant fungal isolates from the four counties. Hierarchical cluster analysis was done using DARwin software V6 to reveal different dissimilarity levels among the isolates based on biochemical and morphological characteristics. Key words: Ralstonia solanacearum, rhizosphere screening, fungal isolates, bacterial isolates, biological control.

Co-migration of phytate with cereal β-glucan and its role in starch hydrolysis in-vitro

This study investigated the mechanisms of the co-migration of phytic acid during β-glucan isolation and its contribution to the retardation of starch hydrolysis in vitro. During the isolation, phytic acid precipitated together with β-glucan when ethanol was added as the precipitation solvent. The precipitation of phytic acid was reduced by lowering the pH or the ethanol concentration. When 20% (NH4)2SO4 was used as the precipitation solvent, only minor phytic acid was found in isolated β-glucan, because phytic acid did not precipitate by this solvent. In the in vitro starch hydrolysis test, the isolated oat β-glucan (OBG) containing 3.9% co-migrated phytic acid showed better retardation effect than OBG containing 0.6% phytic acid. Therefore, we concluded that the co-migration of phytic acid was dependent on the chosen isolation procedure and conditions, and both intrinsic phytic acid and viscosity contributed to the retardation of starch hydrolysis.

Culture Dependent Examination of Commercially Available Bar Chocolates

In the year 2018 a report published by TechSci Research entitled “India Chocolate Market Forecast and Opportunities, 2018” reiterated that the chocolate market earnings in India has witnessed the growth rate of 21% from 2013-2018. Indian chocolate market witnessed USD 3.2 billion revenues in 2018. Indian chocolate market is divided into 4 sectors, in which bar chocolates accounts for highest share of 36%. Hence, We had chosen to study the commercially available bar chocolates through culture dependent methods. We had selected 3 commercially available bar chocolates namely Cadbury Dairy milk, Cadbury 5 Star and Cadbury Perk. Bacteria were isolated from these 3 brands of chocolate by streak plate method. Microbiological and Biochemical assays such as Simple staining, Gram staining, Catalase test, Methyl Red test, Oxidase test, Vogus Proskaur test, Indole test, Citrate utilization test and Starch hydrolysis test were performed. The bacterial isolates were found to be Rod shaped and Gram negative. The bacterial isolates were found to be negative for all the above mentioned tests except Methyl Red and Starch hydrolysis test. Thus, these findings highlight the impending health hazard posed by the commercially available bar chocolates.

Isolation And Characterization Of Gut Bacterial Species Of Earthworm Lampito Mauritii

Lampito mauriti is an Anecic earthworm living in the topsoil and it is geophytophagous in nature.This earthworm is an important soil macro fauna as it has the dual role of an ‘ecosystem engineer’ due to the ability to build burrows as well as ‘keystone species’ in soil food webs because of its function in degradationof organic wastes. The present study investigates the gut of this earthworm to find the most predominant bacterium harbored inside. Gut contents were extracted and streaked on bacteriological media. The predominant type of colony was identified based on size, pigmentation, form, margin and elevation. Thendifferent colonies were isolated and streaked separately to get pure colonies. The bacteria was subjected to several biochemical tests like Motility test, Gram staining, Methyl Red test, Voges-Proskauer test, Indole production test, Carbohydrate Fermentation test, Catalase test and Starch Hydrolysis test in order to identify the species. The bacterial species identification was done using Bergey’s manual. The bacterial isolates such as Micrococcus spp, Veillonella spp, Bacillus spp and Streptococcus spp were identified.

Prevalence of Multi-Drug Resistance Traits in Probiotic Bacterial Species from Fermented Milk Products in Bangladesh

Aims: Matured nourishment like yogurt and cheese are great wellsprings of probiotic living beings. The present study was carried out for isolation, identification and antibiotic profiling of some important bacteria in, local fermented milk-products sold in the market of Dhaka, Bangladesh.
 Methodology: Twenty types of yogurt and fifteen types of cheese samples were collected from two different local market. De Man, Rogosa and Sharpe agar (MRS agar) and Streptococcus thermophilus agar (ST agar) were used for the isolation of probiotic micro-organisms from these different fermented dairy products. Characterization of lactic acid bacteria belonging to the species of Lactobacillus acidophilus, Lactobacillus bulgaricus and Streptococcus thermophilus was done by using morphological feature, Gram staining, biochemical tests (catalase test, some carbohydrate fermentation tests, alpha haemolysis test, starch hydrolysis test, bile salt tolerance test). The antibiotic profiling was performed by utilizing twelve distinct antibiotics: amikacin (10 μg), amoxicillin (15 μg), azithromycin (30 μg), bacitracin (30 μg), chloramphenicol (30 μg), ciprofloxacin (10 μg), erythromycin (30 μg), gentamicin (30 μg), kanamycin (30 μg), penicillin g (30 μg), tetracycline (15 μg), vancomycin (15 μg) to identified the multi-drug resistance of probiotic micro-organisms.
 Results: The outcomes demonstrated that specific bacterial species (L. acidophilus, L. bulgaricus and S. thermophilus) were utilized in the production of yogurt and cheese samples, that may have unnecessary antibiotic resistances which can be a risk if they transfer antibiotic resistance genes to pathogenic microbes. Notably, L. bulgaricus was effectively susceptible against bacitracin and penicillin g.
 Conclusion: Yogurt and cheese are one kind of probiotic source, made up by using probiotic starter cultures (Lactobacillus spp. and Streptococcus thermophilus) which were identified in this study. Most of the probiotic micro-organisms were resistant against these widely accepted commercial antibiotics. These resistant lactic acid bacteria may transfer their resistance genes to pathogenic microorganisms. It can be a significant cause of concern for human and animal health.

EXTRACTION & PURIFICATION OF HEMOLYSIN FROM TOXIN PRODUCING MICROORGANISMS AND ITS EFFECT ON FORENSICALLY IMPORTANT BLOOD AND SALIVA SAMPLES

Examination of Blood and saliva samples in forensic investigation is now become crucial part of judiciary as it can be useful for the identification of an individual. Individual can be identified from such biological samples by blood grouping as well as DNA analysis. In the study isolation of microorganisms was done from different surfaces having highest possibility of presence of biological evidence, Gram staining and morphological characterization of microorganisms was done, the extraction of toxin from toxin producing microorganism which was determined by the zone of hemolysis on blood agar media was done by ammonium sulphate and sodium azide method. Purification was done and confirmation of toxin was done by ditch method, TLC & SDS-PAGE. Effect of toxin on blood was examined by Drabkin’s method for determining hemolytic unit. Effect of hemolysin on saliva was examined by starch hydrolysis test as well as loss of an antimicrobial Property of saliva. As the toxin isolated is hemolysin toxin means it degrades the blood, but in the study we observed the effect of the hemolysin toxin on saliva as well. As mentioned in results blood samples loses its ABO blood grouping activity as it got affected by toxin. Saliva was also highly affected by toxin isolated, as the saliva loses the amylase activity and antimicrobial activity as well. The study is significant in cases where blood and saliva may found as crucial evidence. As RBCs and surface antigens got degraded by hemolysin blood as evidence may be undetectable by presumptive test and may give false results. Saliva samples also become untraceable during the presumptive test as loses its amylase activity.

Deciphering rhizosphere microbiome for the development of novel bacterial consortium and its evaluation for salt stress management in solanaceous crops in India

Eighty bacteria were isolated from the salt affected solanaceous crops (potato, tomato, chilli and brinjal) rhizosphere and fallow land in Mau, Faizabad, Ballia, Gazipur and Varanasi districts of Uttar Pradesh, India. All the bacterial isolates showed morphological variation on Nutrient agar, Jenson’s medium, Modified Czapek-Dox medium, Mannitol egg yolk polymyxin agar, Pseudomonas isolation agar medium, Luria Bertni agar, Tryptic soya agar, King B agar and Nutrient broth yeast extract. Majority of the isolates showed creamy colony (32.5%), spherical (66.25%), shiny (88.7%), raised (62.25%), translucent (71.25%) and entire type of surface margin (78.75%). The gram staining, catalase test, glucose fermentation, IAA test, H2S production, starch hydrolysis, tween 80, gelatin hydrolysis, casein hydrolysis, P solubilization, Zn solubilization and ammonia production tests revealed that 26, 28, 13, 3, 11, 10, 18, 10, 17, 24, 23 and 16 isolates were positive for these tests respectively. The molecular characterization of bacterial isolates Brevibacillus fluminis, Brevibacillus agri, Bacillus paralicheniformis, and Microbacterium arborescens revealed that these are highly salt tolerant (18%) produced 37 alleles using box primer. The number of bands (400–3190 bp) varied from 1 to 10. A cluster analysis with unweighted pair-group method with arithmetic means (UPGMA) based on Jaccard’s similarity coefficient divided the bacterial isolates into two major and three minor clusters with coefficient of similarities ranging from 1 to 23%. Phylogenetic analysis of salt tolerant bacterial isolates showed that out of 22 isolates, 17 (77.27%) were found to be phylogenetically closely related to Bacillus, with 99–100% similarity in their 16S rDNA sequences, making Bacillus the most dominant genus among salt tolerant bacteria in the study.

Studies on the Influence of Mixed Culture from Buried Soil Sample for Biodegradation of Sago Starch Filled Natural Rubber Latex Gloves

The addition of sago starch into natural rubber (NR) latex compounds was aimed to accelerate the degradation process of the end products including gloves as an alternative to reduce solid waste disposal problem. In this research work, the degradation of sago starch filled natural rubber (SS/NR) latex gloves by a mixed culture from buried soil sample was investigated. The Gram staining test of mixed culture showed the Gram-negative bacteria are the dominant species as an effective bacterium to degrade the SS/NR latex gloves. The starch hydrolysis test was performed to confirm the existence of starch-degrading bacteria in mixed culture that consume sago starch from the gloves. Based on the biodegradation rate results obtained, the existence of starch-degrading bacteria together with rubber-degrading bacteria were observed, which accelerate the biodegradation of SS/NR latex gloves by 53.68%. Meanwhile, the biodegradation rate for sago starch unfilled natural rubber (control) latex gloves were only 50.31%. Thus, the addition of sago starch has shown an increased in the biodegradation rate, which can be used as alternative method to overcome the solid waste disposal problem.

Isolation and Characterization of Acetoacetic Bacteria from Decomposed Fruits

Acetic Acid Bacteria (AAB) are rod shaped, aerobic, and gram-negative bacteria. These have ability to oxidize ethanol to acetic acid and are used in vinegar production.The aim of this study was to isolate and identify the acetic acid bacteria which are capable of growing at 30-40oC, temperature generally prevalent in this area for most of the year. Microorganisms were isolated from decomposed fruits like banana, pear, and orange obtained from local vegetable market. We used specific culture media viz.isolation, enrichment and peptone agar media. The samples were inoculated in sterilized GYC standard media and then incubated at 30°C for 48 hours. Successive subculture was performed to screen out the strains. In Gram’s staining, the morphology of the isolated bacteria exhibited pink and rod shaped. Various biochemical tests of the isolated strain like starch hydrolysis,methyl red,and ketogenesiswere positive, while starch hydrolysis and cellulose test were negative which revealed that the strain isolated from decomposed fruits were acetic acid bacteria. The study indicated that all the strains grew well at pH 5-6 and temperature28oCto30oC.

Identification of Pseudomonas fluorescens using different biochemical tests

Pseudomonas fluorescens not only enhances the plant growth but also controls the fungal pathogens by production of anti fungal metabolites. The objective of this experiment was to identify P. fluorescens using different biochemical tests. This research was carried out in Plant Pathology Laboratory at Agriculture and Forestry University (AFU), Rampur, Chitwan, Nepal. The result of this experiment indicated that P. fluorescens gave positive result for Catalase test, Gelatin liquefaction, Fluorescent pigment and Oxidase test but negative result for starch hydrolysis test. The colony of P. fluorescens was maximum in maize seed than that of rice seed after two hours of inoculation, whereas higher number of colony was found in rice seed than that of maize seed after twenty four hours of seed inoculation. This findings is useful for identifying colony of P. fluorescens per seed which is necessary for better seedling growth and effective biological control of pathogens.

Isolation, identification and evaluation of oil hydrocarbon decomposing bacteria from contaminated areas of oil fields

Microbialbiodegradation is known as an effective and harmless method to overcome environmental pollution with oil hydrocarbon. Some bacterial species were isolated from the Sarvestan oilfields (Iran, Fars province), then identified and applied for oil hydrocarbon decomposition. A carbon-free minimum medium (CFMM) containing 1% crude oil was used to isolate bacteria through incubation at 30°C in the dark at 200 rpm for 7 days. Different methods were used to identify the hydrocarbon oil decomposing bacteria: gram staining, squalene hydrolysis, catalase, production of arginine dihydrolase, gelatin liquefaction, hydrogen sulfide production, levan production, methyl red, oxidase, nitrite reduction, oxidative/fermentative, starch hydrolysis and Tween-80 hydrolysis tests. Nine different oil decomposing bacterial species were isolated. All the species grew well at 28 and 35°C, while four isolates containing of Bacillus sp. SA13, Pantoea sp. SA1112, Pseudomonas aeruginosa sp. SA21, and Bacillus sp. SA23 were capable of growing in a temperature of up to around 42°C. The minimum salt tolerance for isolates, except for Enterobacter sp. SA711, was 8%; Bacillus sp. SA212 had the highest tolerance of 15% sodium chloride. Acinetobacter sp. SA172, Enterobacter sp. SA711, Pseudomonas sp. SA75, Bacillus sp. SA212 and Bacillus sp. SA23 had the most growth rate in the CFMM. The highest percentages of oil removal obtained were 89% for Enterobacter sp. SA711, 86% for Acinetobacter sp. SA172, and 68% for Pseudomonas sp. SA75. The three isolated bacterial strains from the contaminated soil of the Sarvestan area had a good ability to degrade oil hydrocarbon. Therefore, they could be used commercially for the bioremediation of this region.

MORPHOLOGY, PHYSIOLOGY AND MOLECULAR CHARACTERISTICS OF OIL PALM (Elaeis guineensis Jacq.) ENDOPHYTIC Bacillus sp.

Endophytic bacteria are the bacteria that live in plant tissues. In oil palm tissue there are many types of endophytic bacteria and have a role that can be beneficial for the plant, one of them is endophytic Bacillus sp. The aim of these research was to obtain morphology, physiology and molecular characteristics of endophytic Bacillus sp. originating from oil palm tissue. Sampling was done by random simple sampling method. Isolation of bacteria was performed on plant tissues such as roots, midribs, stems and leaves of oil palm plants. The results of morphological characterization such as colony color, colony shape and colony edge show similarity in each isolate but there are differences in the surface morphology of the colony, where there are 6 isolates with convex surface and 6 isolates with flat shape. Physiological test results such as catalase test, oxidase test, starch hydrolysis test, motility test and temperature effect test on bacterial growth showed positive results in each isolate. Molecular characterization using 16S rRNA primers based on BLASTn shows that all isolates tested have similarities with Bacillus sp. Based on the phylogenetic tree it was found that the endophytic bacteria of Ba-B2 isolates were associated with Bacillus flexus with 100% consistency index grouped at a distance of 0.03 and Ba-P2 isolates were related to Bacillus substilis at a distance of 0.01 with an 89% consistency index.

Production of thermostable extracellular α-amylase by a moderate thermophilic Bacillus licheniformis isolated from Qinarje Hot Spring (Ardebil prov. of Iran)

Background and Purpose: Amylases are most important industrial enzymes that account for about 30% of the world’s food, feed, fermentation, textile, detergent and cellulosic industries. This study aimed at optimum production of thermostable α-amylase via moderate thermophilic bacterium (Bacillus licheniformis) which was recently isolated from Qinarje Hot spring.Material and Methods: Initially, ability of bacterium for amylase activity was determined by starch hydrolysis test using Gram’s iodine staining. Then bacterial growth pattern and amylase production curves in basal production medium were graphically determined at different time intervals. Finally, effect of different temperature, pH, carbon source, nitrogen source, minerals and inoculum size were studied on bacterial growth and amylase production using turbidimetric and DNS method, respectively.Results: Optimum enzyme production achieved after 84 hours of inoculation from cultures growing at 40 ˚C and pH 9.0 in a medium containing 0.03% (w/v) of CaCl2, compared to the basal medium, results showed that the best enzyme production happened with inoculum size of 4% (v/v). The addition of 1% (w/v) rice husk (as a Carbon source) enhanced enzyme productivity up to 160% and substitution of the peptone and yeast extract with 1% (w/v) of tryptone (as a Nitrogen source) increased the α-amylase production up to 160%.Conclusion: Our findings show that B. licheniformis-AZ2 strain has an ability to produce the thermostable α-amylase which is suitable in starch processing and food industries. To be commercialized, further investigation is required for enhancement of the enzyme production.Keywords: Bacillus licheniformis; Optimization; Basal medium; Agricultural by-products.

Isolation and Characterisation of Ralstonia Solanacearum Strains of Tomato Wilt Disease from Maseno, Kenya

Ralstonia solanacearum (E.F. Smith) Yabuuchi, is the cause of bacterial wilt of tomato and one of the most severe pathogens of solanaceous crops with a very wide host range. There is little information on R. solanacearum strains in Maseno region in Kenya despite the fact that bacterial wilt of tomato is of economic importance. The objective of this study was to isolate the strains of R. solanacearum of tomato and characterize morphologically and biochemically Ralstonia solanacearum races and biovars from infected tomato plants in Maseno region. This study was conducted at Maseno University in the Department of Botany at Microbiology Laboratory. Ten diseased tomato plants from Maseno, Mariwa, Seme and Hollo were collected and cut into small sections (0.5–1cm). The plant sections were then plated onto Triphenyl tetrazolium chloride (TZC) media. Profiling of the pathogen was done morphologicaly using culture techniques; biochemical tests included Gram staining test, Potassium hydroxide test, Catalase oxidase test, Gas production test, Starch hydrolysis test and sugar utilization test. The races were then identified by pathogenicity test on wide host range. All the isolates had fluidal pinkish red centered colonies on TZC media, they were Gram negative, potassium hydroxide solubility positive, produced gas from glucose, ooze test positive and did not hydrolyse starch which is typical of R. solanacerum. R. solanacearum strains from infected tomato plants in Maseno region were race 3 biovar 1 and race 3 biovar 3. All isolates were pathogenic on tomato plants.

Potato peels: A potential food waste for amylase production

AbstractIn the present study, thermophilic and amylase producing bacterium Bacillus subtilis K‐18 (KX881940) was isolated from local environment and identified by 16S rRNA gene sequencing technology. The amylase producing potential was checked by starch hydrolysis test using potato peels as carbon source. Central composite design (CCD) of response surface methodology (RSM) was used to optimize multiple process parameters such as substrate concentration, inoculum size, yeast extract, and pH. The optimized conditions obtained from RSM model were substrate concentration (2%), inoculum size (4%), yeast extract concentration (0.6%), and pH (5) yielding amylase activity of 1394.145 IU/ml after 24 hr of fermentation period at 50 °C. The maximum saccharification by indigenously produced amylase was 32.03% after 24 hr of incubation. The results confirmed that amylase produced by this newly isolated Bacillus subtilis K‐18 (KX881940) could be potent strain for industrial process particular for biofuel production.Practical applicationThe enzyme produced in this study could be effectively used in hydrolysis of starch to produce sugars which could be widely used for the production of various chemicals such ethanol and other products through fermentation. This enzyme also has potential application in textile industry.

Virulence assay and role of Bacillus thuringiensis TS110 as biocontrol agent against the larval stages of rice leaffolder Cnaphalocrocis medinalis.

The bacterial isolate Bacillus thuringiensis TS110 was isolated from the rice field soil of Burdwan district, West Bengal, India. Bioassay test of the bacteria TS110 against 3rd, 4th and 5th instar larvae of Cnaphalocrocis medinalis was carried out. Cut leaf assay, potted plant assay and field assay were done. During filed assay, it has been observed that the LC50 (×107) values of TS110 against 3rd, 4th and 5th instar larvae of C. medinalis were 3.77, 5.29, 4.83 and 4.93, 4.42, 4.72 in dry and wet season, respectively. The morphological, biochemical and phylogenetic analysis of the isolate TS110 were done. TS110 was positive for catalase, nitrate reductase, methyl red, voges-proskauer, oxidase, urease, indole, citrateutilization, arginine dihydrolasetest, starch, lipid, gelatin, casein, and lecithin hydrolysis test. TS110 showed fermentation test positive for glucose, fructose, mannose, arabinose and trehalose in nutrient broth medium. The antibiotic sensitivity test showed that the bacterial isolate was sensitive to kanamycin (30µg/disc), nalidixic acid (30µg/disc), rifampicin (5μg/disc), doxycycline (30µg/disc), gatifloxacin (10µg/disc), vancomycin (30µg/disc), gentamycin (10µg/disc), ampicillin (10µg/disc), ofloxacin (5μg/disc), levofloxacin (5μg/disc), streptomycin (10µg/disc), gentamycin (10µg/disc). The phylogenetic analysis revealed that TS110 was closely related to different species of B. thuringiensis submitted to the GenBank. On the basis of morpho-physiological and molecular characterization, the bacterial isolatewas identified as B. thuringiensis.