Chitinase-producing Bacterium Research Articles

Isolation, screening, and identification of chitinase-producing bacterial strains from riverbank soils at Ambo, Western Ethiopia

Chitinases are hydrolytic enzymes that dissolve the glycosidic linkages in chitin. Chitin is a cell wall component of fungi and fund in exoskeleten of worms and arthropods. Chitinase has been applied in agriculture, as a biopesticide for the control of plant fungal infections, in medicine, and in waste management. This research aimed to isolate, screen, and identification of chitinase-producing bacteria from riverbank soils. Twenty nine chitinolytic bacteria were isolated from the river bank soil samples, from which 9 of them had strong chitinolytic properties. Chitinase production was determined by zones of hydrolysis produced after 96 h of incubation at 37 °C. The different bacterial isolates were characterized morphologically, microscopically, and biochemically and finally eight strain were identified at species level by Matrix Assisted Laser Desorption Ionization - Time of Flight Mass Spectrometry (MALDI–TOF MS). From the eight, bacterial isolates investigated in this study Stenotrophomonas maltophilia showed the highest chitinase enzyme activity (625 μg/mL) followed by Pseudomonas putida with the enzyme activity of (553 μg/mL) and the least enzyme activity was recorded for Lilliottia amnigena (80 μg/mL). An incubation temperature of 45 °C, neutral pH and an incubation period of 96 h are found to be the optimum condition for the chitinase enzyme production from Stenotrophomonas maltophilia. The results of this study indicated the possibility of the production of chitinase from the chitinolytic bacterial isolates, which was highly useful for a variety of applications, including biocontrol of harmful insects and pathogenic fungi as well as in the biochemical, pharmaceutical, and medical sectors.

Identification and characterization of chitinase-producing bacteria from gut of pleurostict scarab beetle grubs (Coleoptera: Scarabaeidae)

Identification and characterization of chitinase-producing bacteria from gut of pleurostict scarab beetle grubs (Coleoptera: Scarabaeidae)

Thermostable Chitinase Producing Bacterium from Ijen Hot Spring – Indonesia: Isolation, Identification, and Characterization

The high industrial demand for thermostable chitinase with new and desirable characteristics has led to the exploration of chitinolytic bacteria from extreme environments. Therefore, this study aimed to isolate, screen, and identify chitinase–producing bacteria from Ijen hot spring, Indonesia. The highest chitinolytic activity bacterium was identified by 16S rRNA gene sequencing and its characteristics were confirmed by morphological and physiological analyses. Chitinase production activity of selected bacterium under variation of agitation and aeration as well as its chitinase properties were characterized afterward. Twelve chitinolytic bacterial colonies were isolated and screened for their growth activity on Thermus colloidal chitin medium, in which chitin was used as the sole carbon source. Among these twelve isolates, isolate B2 showed the highest chitinolytic activity. The molecular, morphological, and physiological analyses confirmed that isolate B2 belonged to Bacillus licheniformis. This isolate produced a huge amount of chitinase on Thermus colloidal chitin medium at 50 °C within 30 h. The highest growth and chitinase production activity were recorded at 3 vvm aeration rate and 300 rpm agitation speed. Chitinase produced by this isolate was optimally active at pH of 7 and temperature of 55 °C and evidently proofed as thermostable due to its high residual activity after several thermal stability tests.

Chitinase enzyme in bacterial species and fungal growth inhibition against A. niger and Penicillium

Chitin is the most abundant polysaccharide in nature, second after cellulose as it found in the structure of crustaceans, insects and fungi being a significant component. Sea food waste disposal pose a great problem as chitin in nature degrade at a very gradual rate. Efforts are being made to use chitinase enzyme from different organisms to increase the rate and efficiency of chitin waste disposal. Moreover, chitinase and chitinase producing bacteria are widely being exploited to be used as bio-control agents to inhibit crop pathogens. On the basis of its mechanism of action, chitinase can either be endochitnase or exochitinase. Endo chitinases randomly hydrolyses internal glycosidic bonds in chitin. Exochitinase is exoglycosidase that can be divided into two subtypes based on the specificity of their action Chitinase is synthesized by a number of different microbes including bacteria, fungi and other organisms like mammals, insects etc. This paper gives information about the production of different chitinase enzymes from different bacterial gram-positive species. Antifungal activity for different isolates were tested against A. niger and Penicillium. The isolates showed varying degree of fungal growth inhibition against different fungi.

DEVELOPMENT OF BIOINSECTICIDES AGAINST SPODOPTERA FRUGIPERDA USING CHITINOLYTIC BACTERIA

Actinomycetes play an important role in the biological control of insects by producing insecticidal active compounds against various insects. They are predominantly found in soil, in the silt of water bodies, in the air and in plant remains. Chitinase is increasingly finding applications in various fields such as biomedicine, in ultra-structural studies, in the preparation of chitooligosaccharides, in single-cell protein production, biocontrol agents, agriculture, etc. Chitinase is originally an enzyme used by insects to degrade the structural polysaccharide of insects. Chitinase brings about hydrolysis of chitin which is widely distributed in cell wall of fungi, plants and insects. An attempt has been made to use chitinase producing bacteria for the development of bioinsecticides against Spodoptera frugiperda, which feeds on over more than 60 species of plants and it is periodic. The Spodoptera frugiperda armyworm (Lepidoptera) is a serious pest of cabbage and other crop. It is also major pest of maize, rice, sorghum, turf grasses, cotton, and peanuts, etc. In this attempt enrichment and isolation of chitinase producing bacteria from soil was carried out. Chitinolytic activities of the three isolates were tested against larvae of Spodoptera frugiperda. Three isolates were individually applied against Spodoptera frugiperda. The isolates named Ai, A2 and A3 were found to be more effective against Spodoptera frugiperda. The insecticidal activity of isolate A1was tested and control within 5 hours. Isolate A2 was treated with larvae Spodoptera frugiperda killed after 8 hours whereas, isolate A3 controlled after 24 hours. The evaluated insecticides provided a significant reduction in the infestation level, for variable periods.

Heat-Stable Antifungal Factor and Expression Patterns of Protease by Chitinase-Producing Bacterium, Pedobacter sp. PR-M6

This study was conducted to investigate the protease expression patterns of the novel chitinase-producing bacterium Pedobacter sp. PR-M6. Protease were detected on SDS-PAGE gel as condition of 4℃, 25℃ and 37℃ to activate of enzymes obtained from incubation of LB, NB and 1% skim milk medium at 4℃, 20℃ and 30℃ after 21 days of incubation, respectively. Pedobacter sp. PR-M6 displayed proteolytic activity on SDS-PAGE gels containing 0.1% (w/v) gelatin, and protease isozymes of PR-M6 were expressed as two major bands (P7 and P8) and seven minor bands (P1, P2, P3, P4, P5, P6, and P9). Protease isozymes of PR-M6 were inhibited at 4℃ and 25℃. The two protease isozymes P5 and P6 were newly expressed in the LB culture medium at 20℃. To investigate the properties of a heat-stable antifungal factor (HSAF), PR-M6 stain was cultured to obtain the products of biosynthesis for incubation in LB medium. HSAF exhibited active biosynthesis at 20℃ for incubation in LB medium. Crude HASF obtained from LB20 medium showed hyphal growth inhibition of Rhizoctonia solani. Inhibition rate of R. solani growth was as high as 67% at 24 h and 47.8% at 48 h after incubation with 1,000 ppm of crude HSAF. Trypan blue stained the inside of the edge for destructed R. solani cell walls after crude HSAF treatment. These results indicated that HSAF and protease from Pedobacter sp. PR-M6 could be used as biocontrol agents against phytopathogens in agriculture.

Bioconversion of chitin waste through Stenotrophomonas maltophilia for production of chitin derivatives as a Seabass enrichment diet

Marine wastes pose a great threat to the ecosystem leading to severe environmental hazards and health issues particularly the shellfish wastes. The shellfish waste which contains half of the amount of chitin can be efficiently transformed into useful products. Various approaches for the hydrolysis of chitin like physical, chemical, and enzymatic processes are there. Still, the use of enzyme chitinase is well documented as an effective and eco-friendly method. The present study summarizes the isolation of chitinase enzyme producing bacteria from different shrimp waste disposal sites in Parangipettai (India), and the possible use of an enzyme hydrolyzate as an immunostimulant to Asian Seabass (Lates calcarifer). The potential chitinase-producing bacteria were identified by 16S rRNA gene sequencing as Stenotrophomonas maltophilia. After purification, the chitinase specific activity was 5.01 (U/ml) and the protein content was 72 mg and the recovery rate was 48.06%. The optimum pH and temperature for the chitinolytic activity were 6.5 and at 35–50 °C, respectively. The animal experiment trial was done with our feed supplements which included 0.0 (control), 0.5%, 1% and 2% of chitin degraded product. All the supplementary feed had an optimal 42% (w/w) of crude protein. The feed protein level was 41–43% on average and gross energy was 13–17 kcal/g and the feed was observed to exhibit a significantly higher (p < 0.05) survival rate, condition factor, specific growth rates, and body weight gain was also found to be promising compared to other fishes fed with control diet only. The red blood cells (RBC) and white blood cell (WBC) counts were found to increase significantly after being challenged with infection in animals fed with chitin derivatives from 1st week to 3rd week when compared to the control. The hematocrit (Hct) values were low on the 2nd and 3rd week in infected fish fed with chitin derivatives. This low level was due to infection lyses of the red blood cells and increased nitro blue tetrazolium reduction. The control diet-fed fish showed 70% mortality but the chitin derivative supplemented fishes showed only 20% mortality post-infection. The results of the study encompass that the use of chitin-derivate enriched feed further is taken into large-scale approaches thereby benefitting the aquaculture sector.

Study of Thermostable Chitinase Isolated and Purified from Oryctes rhinoceros Larvae Gut

A chitinase-producing bacteria was locally isolated from rhinoceros beetle (Oryctes rhinoceros) larvae gut discovered in mushroom compost. A strain was selected from the source and labeled as RBLG1. It was identified using 16s rDNAsequencing and has strong homology to Bacillus cereus. Chitinase produced from RBLG1 was purified using ammonium sulfate precipitation, ion exchange chromatography, and gel filtration. The purified chitinase from RBLG1 shows the homogeneity 1.9 fold after the gel filtration process. The purified chitinase was identified and analyzed using SDS-PAGE and the molecular mass from the strain was approximately 40 kDa. Further assays were performed to study the effect of temperature, pH, and metal ion on the purified enzyme. The purified enzyme shows highest chitinase activity at pH 4 and 60 °C. For metal ion test, chitinase from RBLG1 was unaffected when treated by various ions. Kinetic performance of chitinase using Michaelis-Menten equation shows Km and Vmax values were 2.3 mM and 0.0294 [P] mM/min, respectively.

Chetoui Olive Cultivar Rhizosphere: Potential Reservoir for Exoenzymes and Exopolysaccharides Producing Bacteria

Rhizospheric soils from cultivated olive (Olea europaea) trees of Chemlali, Chetoui, Quaissi, and Djalat cultivars were assessed for their bacterial abundance and diversity and were further screened for production of exopolysaccharides and exoenzymes (cellulase, chitinase, amylase, protease, lipase, and peroxidase). The results of the present study indicate that Chetoui cultivar revealed higher diversity, followed by Chemlali &gt; Quaissi &gt; Djalat, wherein, bacilli, enteric bacteria, and pseudomonads were abundantly present as specific bacterial groups associated with the Chetoui rhizosphere. Moreover, the exopolysaccharide (EPS)-producing bacteria of Chetoui cultivar (68.4%) presented the highest efficiency, followed by Djalat (23.5%) &gt; Chemlali (7 %) &gt; Quaissi (1%). These results revealed that the Chetoui cultivar presented highest enzyme activities, followed by Chemlali &gt; Djalat &gt; Quaissi, with a distinct abundance of peroxidase- and chitinase-producing bacteria, which may play a pivotal role in adapting olives to the environmental stresses. From this preliminary study, we confirmed that olive rhizosphere microbial diversity is essentially driven by the geographical origin and genotype of olive cultivars. Furthermore, we recommended the Chetoui olive cultivar rhizosphere as a potential reservoir for exoenzyme- and EPS-producing bacteria useful for future biotechnological applications.

Cloning, isolation, and characterization of novel chitinase-producing bacterial strain UM01 (Myxococcus fulvus)

BackgroundChitin is an important biopolymer next to cellulose, extracted in the present study. The exoskeleton of marine bycatch brachyuran crabs, namely Calappa lophos, Dromia dehaani, Dorippe facchino and also from stomatopod Squilla spp. were used to extract chitin through fermentation methods by employing two bacterial strains such as Pseudomonas aeruginosa, Serratia marcescens. The yield of chitin was 44.24%, 37.45%, 11.56% and 27.24% in C. lophos, D. dehaani, D. facchino and Squilla spp. respectively. FT-IR spectra of the produced chitin exhibit peaks which is more or less coherent to that of standard chitin which is further analysed by Scanning Electron Microscope. The quality of produced chitin was assessed through moisture, protein, ash and lipid content analysis ensured that chitin obtained from trash crustaceans are on par with that of standard chitin. ResultsA total of 10 samples were collected from different areas of Jiangsu China for screening of chitinase-producing bacteria. Based on the clearance zone, two of the best samples were chosen for further study. 16S rRNA sequence analysis showed that this strain belongs to genus Myxococcus and species Myxococcus fulvus. Phylogenetic analysis was performed and it shows strain UM01 is a novel bacterial strain. UM01 isolate shows maximum chitinase production at 35 °C and 8 pH. Among all, these colloidal chitins were found to be the best for chitinase production. Three chitinase-producing genes were identified and sequenced by using degenerative plasmid. UMCda gene (chitin disaccharide deacetylase) was cloned into E. coli DH5a by using PET-28a vector, and antagonistic activity was examined against T. reesei. ConclusionTo our knowledge, this is the earliest study report to gene cloning and identification of the chitinase gene in Myxococcus fulvus. Chitinase plays a key role in decomposition and utilization of chitin as a raw material. This research indicates that Myxococcus fulvus UM01 strain is a novel myxobacteria strain and can produce large amounts of chitinase within a short time. The UMCda gene cloned into E. coli DH5a showed a promising effect as antifungal activity. In overall findings, the specific strain UM01 has endowed properties of bioconversation of waste chitin and other biological applications.

Chitinase Production from Locally Isolated Bacillus cereus GS02 from Chitinous Waste Enriched Soil

Background and Objective: Chitin is world’s second most abundant structural carbohydrate in nature and is found as a structural component in the cell wall of fungi and exoskeletons of invertebrates. During senescence, it is degraded by the enzyme, chitinase. In addition, chitinase has been exploited for various commercial applications such as control of insects and fungal pathogens in order to protect the crops, waste management, cosmetics and food industries. Chitinases have been found to be widely distributed in various organisms including viruses, animals, bacteria, fungi, higher plants and insects. In the present study, various soil samples enriched in chitinous waste were screened for the isolation of bacteria capable of producing chitinase.&#x0D; Methodology: Chitinase producing bacteria were isolated using serial dilution plating technique onto different agar media. Primary and secondary screening were performed and the isolate producing maximum chitinase was selected for biochemical identification and 16s rRNA sequencing. The secretion of extracellular chitinase by this strain was optimized with respect to pH, temperature, incubation time, substrate concentration, carbon and nitrogen sources and inoculum size. All these components were optimized using OFAT (one factor at a time) approach.&#x0D; Results: A total of 29 bacterial isolates were found exhibiting secretion of extracellular chitinase as determined using zones of clearance. Based on the area of zone of clearance, six isolates were selected for secondary screening and the most potent isolate was identified as Bacillus cereus. The maximum chitinase production by this strain was obtained at 37°C and pH 7.0 after 48 hours of incubation. The maximum chitinase secretion was observed on addition of 1% colloidal chitin and 0.05% yeast extract in the medium.

Purification and characterization of chitinase from Paenibacillus sp. .

The chitinase-producing bacteria Paenibacillus sp. was isolated from soil samples. The chitinase was purified successively by ammonia sulfate fractional precipitation followed by chromatography on DEAE 52-cellulose column and then on SephadexG-75 column. The chitinase has a molecular weight of ca. 30 kDa as measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) electrophoresis. Its optimum pH is 4.5, and its optimum temperature is 50°C with colloidal chitin as a substrate. The enzyme is stable below 45°C and in pH ranges between 4.5 and 5.5. It is activated by glucosamine, glucose, N-acetylglucosamine, and metal ions including Ca2+ , Fe2+ , Fe3+ , and Ni2+ . It is inhibited by SDS, H2 O2 , ascorbic acid, Cu2+ , Mg2+ , Ba2+ , Sn2+ , Cr3+ , and K+ . With colloidal chitin as substrate, the Km and the Vmax of the chitinase are 4.28 mg/mL and 14.29 μg/(Min·mL), respectively, whereas the end products of the enzymatic hydrolysis are 14.33% monomer and 85.67% dimer of N-acetylglucosamine. The viscosity of carboxymethylchitin decreased rapidly at the initial stages when subjected to chitinase hydrolysis, which indicates that the chitinase acts in an endosplitting pattern.

Seleksi dan Karakterisasi Bakteri Penghasil Kitinase Penghambat Pertumbuhan Cendawan Patogen Tanaman

Colletotrichum capsici and Fusarium oxysporum are pathogenic fungi that cause anthracnose disease on chili plants (Capsicum annum L.) which can decrease the productivity of chili. The control of the fungus attack is carried out by biocontrol agent of the fungi utilizing chitinase-producing bacteria. Chitinase is an enzyme capable of destroying the fungal cell wall composed of chitin compounds. The aims of the research were to select and to characterize chitinase producing bacteria as biological control agent of Colletotrichum capsici and Fusarium oxysporum. Several methods were carried out in this research, among others: isolation of chitinase bacteria, characterization of chitinase bacteria, measurement of enzyme activity, bacterial antagonistic with pathogenic fungi, observation of fungal hypha damage, and identification of 16S rRNA. The BAE36 and BAD211 isolates are chitinase bacteria isolated from chili plant rhizosphere. The isolate belongs to the Gram-negative bacteria. The inhibitory properties of BAE36 and BAD211 against F. oxysporum and C. capsici are on a scale of 3 (51-75%). The percentage of inhibitory of BAE36 isolate was 66.1% capable of inhibiting the growth of C. capsici and 55% capable of inhibiting the growth of F. oxysporum. The hyphae of C. capsici fungus on the antagonistic test showed a thick and the surface of the hyphae was wavy while the F. oxysporum hyphae was thin and looks empty. Identification of isolate with 16S rRNA described that 99% of BAE36 and BAD211 isolates were similar to Lysobacter enzymogenes. Precipitation of chitinase enzyme of Lysobacter enzymogenes with 30% ammonium sulphate could increase the enzyme activity. The enzyme precipitation could inhibit the growth of mycelia fungi C. capsici and F. oxysporum. Keywords: chili, chitinolytic, Gram-negative, Lysobacter

Isolation and Molecular Identification of Two Chitinase Producing Bacteria from Marine Shrimp Shell Wastes.

Chitinase enzymes have a various application in the field of environmental, biotechnology and medical aspects. This study aimed to the production of the chitinolytic enzymes from different species of bacteria. Bacterial isolation from different habitats was carried out on agar medium containing chitin as carbon and nitrogen sources. The obtained bacteria (20) were characterized and screened again in chitin broth medium. Out of 20 bacterial isolate, 2 new isolates, belonged to Streptomyces laurentii SN5 and Cellulosimicrobium funkei SN20, were the most active in chitin degradation compared to the other isolates. They have been characterized for the first time for their chitinase activity. They were identified using 16S rRNA gene analysis and in the liquid medium, the 2 isolates have enzyme activities of 0.533 and 0.537 U mL-1, respectively. The maximum chitinase production was obtained when those bacterial strains were grown in Luria-Bertani (LB) broth amended with 1% colloidal chitin, for 1 day and at temperature of 30°C. The optimum pH value for chitinase production was pH 7 for both S. laurentii and C. funkei. The enzyme has been purified using Sephadex G-100 and DEAE-Cellulose chromatography column and found to have a similar molecular size of ~50 kDa. Those two bacterial species could be used in chitinase production and in the environmental recycling of disposable chitin wastes such as chitin from shrimp shell waste.

A Cold-Adapted Chitinase-Producing Bacterium from Antarctica and Its Potential in Biocontrol of Plant Pathogenic Fungi.

To obtain chitinase-producing microorganisms with high chitinolytic activity at low temperature, samples collected from Fildes Peninsula in Antarctica were used as sources for bioprospecting of chitinolytic microorganisms. A cold-adapted strain, designated as GWSMS-1, was isolated from marine sediment and further characterized as Pseudomonas. To improve the chitinase production, one-factor-at-a-time and orthogonal test approaches were adopted to optimize the medium components and culture conditions. The results showed that the highest chitinolytic activity (6.36 times higher than that before optimization) was obtained with 95.41 U L−1 with 15 g L−1 of glucose, 1 g L−1 of peptone, 15 g L−1 of colloid chitin and 0.25 g L−1 of magnesium ions contained in the medium, cultivated under pH 7.0 and a temperature of 20 °C. To better understand the application potential of this strain, the enzymatic properties and the antifungal activity of the crude chitinase secreted by the strain were further investigated. The crude enzyme showed the maximum catalytic activity at 35 °C and pH 4.5, and it also exhibited excellent low-temperature activity, which still displayed more than 50% of its maximal activity at 0 °C. Furthermore, the crude chitinase showed significant inhibition of fungi Verticillium dahlia CICC 2534 and Fusarium oxysporum f. sp. cucumerinum CICC 2532, which can cause cotton wilt and cucumber blight, respectively, suggesting that strain GWSMS-1 could be a competitive candidate for biological control in agriculture, especially at low temperature.

Biocontrol of Botrytis cinerea by chitin-based cultures of Paenibacillus elgii HOA73

The chitinase-producing bacterium, Paenibacillus elgii HOA73, is a biocontrol agent that limits the damage caused to plants by microbial pathogens, insects, and nematodes. However, the mechanisms involved in the biocontrol of plant diseases by HOA73 have not been determined. The objective of this study was to elucidate the role of extracellular chitinase obtained from isolate HOA73 in the control of the fungal pathogen Botrytis cinerea, the causative agent of gray mold in tomato. The HOA73 strain grew efficiently in a chitin-containing broth and produced chitin oligomers through chitinase activity; protease, lipase, and Fe-chelating siderophores were also secreted by the bacterium. Cultures containing intact bacteria inhibited B. cinerea conidia germination to a greater extent than did the bacterial cells alone or the cell-free culture supernatant. The antifungal activity increased with culture age and was heat-sensitive because of chitinase-mediated production of long-chain chitin oligomers. The biocontrol efficacy of undiluted bacterial cultures against gray mold in tomato was comparable to that of a standard fungicide. This study demonstrated that P. elgii HOA73 bacterial cultures grown on chitin-based minimal medium may be an effective formulation for the integrated control of gray mold.

Effect of plant growth-promoting bacteria Bacillus amylliquefaciens Y1 on soil properties, pepper seedling growth, rhizosphere bacterial flora and soil enzymes

The Bacillus amyloliquefaciens Y1 strain was evaluated for its effects on soil properties, pepper seedling growth, rhizosphere bacterial flora and soil enzyme activities. Y1 solubilised insoluble phosphate, produced chitinase, and released siderophores in plate detection assay. In order to evaluate the plant growth promotion potential in vivo, strain Y1 was grown in media containing chitin powder and complex fertiliser. The pot experiment was conducted by treating pepper seedlings with C1/1 (Y1 culture, 50 ml), C2/3 (Y1 culture, 33 ml), C1/2 (Y1 culture, 25 ml), F1/1 (complex fertiliser, 50 ml), F1/2 (complex fertiliser, 25 ml), and W (water) at 10, 20, 30, 40, and 50 days after transplantation (DAT). Plants receiving Y1 had 52% (C1/2) and 68% (C1/1) more root and shoot biomass than W, and 14% (C1/1) and 18% (C2/3) more compared to F1/1 at 80 DAT. Total numbers of flowers per plant at 80 DAT were found significantly higher with the application of Y1 having 34 (C1/1), 35 (C2/3), and 22 (C1/2) compared to 4 (W), 12 (F1/1) and 10 (F1/2). In addition, chlorophyll content in pepper leaves was found to improve with the application of Y1. Furthermore, Y1 has significantly improved nutritional assimilation of total NPK, population of total culturable bacteria and chitinase producing bacteria and activities of chitinase and dehydrogenase in soil. At 60 and 80 DAT, the number of B. amyloliquefaciens at C1/1, C2/3, and C1/2 ranged from 2.3 × 10&lt;sup&gt;4&lt;/sup&gt; to 4.6 × 10&lt;sup&gt;4&lt;/sup&gt; CFU/g of soil. Our results concluded that B. amyloliquefaciens Y1 has positive effects on soil properties and can be suggested as a bio-fertiliser to minimise fertiliser application in modern agriculture.

Penapisan dan Identifikasi Bakteri Kitinolitik Penghambat Pertumbuhan Ganoderma boninense in Vitro

Chitinolytic bacteria have been reported as biocontrol agents and have the ability to produce chitinase enzymes. The objective of the research was to obtain chitinase producing bacteria that had antagonistic activity to Ganoderma boninense , a causal agent of basal stem rot on oil palm. A total of 63 isolates of chitinase producing bacteria were isolated from soil of Bukit Dua Belas National Park and oil palm plantation in Jambi Province; all was screened for their potency in inhibiting G. boninense in vitro . Three isolates designated TB04-05, SW01-11, and SW02-08 were potentially suppressed and inhibited the mycelium growth of G. boninense in vitro . Based on their specific chitinase activity, these three isolates produced the highest level of chitinase enzyme of 6.3072 U mg-1 protein, 6.0385 U mg-1 protein and 6.1279 U mg-1 protein, respectively after 24 hr incubation. Based on 16S RNA identification, strain TB04-05 had similarity with Bacillus cereus, whereas strains SW01 and SW02-08 had similarity with Bacillus thuringiensis.

키틴분해세균의 현장 대량 배양방법을 이용한 효과적인 식물병의 생물적 방제 전략

Recent worldwide demand for organic and sustainable agriculture products is driving the development of formulations of biopesticides effective in the field. Biopesticides have the benefit of environmentally-friendly qualities. However, biocontrol approaches largely have been ineffective in controlling plant pests in field conditions. Previously, we developed a cost-effective biocontrol formulation containing chitin and chitinase-producing biocontrol bacteria with field efficacy. This formulated product has successfully suppressed various plant diseases in the field conditions. In this review, we focus on ecological aspects and the potential mechanisms underpinning the success of chitinase-producing bacteria. In addition, we discuss the possibility on-site cultivation of the formulated products to further strengthen the approach as being farmer friendly and successful.

Chitinase-producing bacteria and their role in biocontrol.

Chitin is an important component of the exteriors of insects and fungi. Upon degradation of chitin by a number of organisms, severe damage and even death may occur in pathogens and pests whose external surfaces contain this polymer. Currently, chemical fungicides and insecticides are the major means of controlling these disease-causing agents. However, due to the potential harm that these chemicals cause to the environment and to human and animal health, new strategies are being developed to replace or reduce the use of fungal- and pest-killing compounds in agriculture. In this context, chitinolytic microorganisms are likely to play an important role as biocontrol agents and pathogen antagonists and may also function in the control of postharvest rot. In this review, we discuss the literature concerning chitin and the basic knowledge of chitin-degrading enzymes, and also describe the biocontrol effects of chitinolytic microorganisms and their potential use as more sustainable pesticides and fungicides in the field.