Chitinolytic Bacteria Research Articles

The qualitative screening of cellulolytic, chitinolytic, IAA-producing, and phosphate solubilizing bacteria from black soldier fly larvae (Hermetia illucens L.)

Black soldier fly (Hermetia illucens L.) larvae are widely used in organic waste management. Its ability to digest organic compound was supported by the diversity of bacteria which produce various enzymes inside the larvae bodies. The exploration of potential bacteria in BSF larvae may have advantages for the agricultural field. This study aimed to screen cellulolytic, chitinolytic, phosphate solubilizing, and IAA-producing bacteria from BSF larvae. A total of 22 isolates were qualitatively screened using various media. Among the 22 isolates, five isolates showed positive results of cellulolytic activity; six isolates were able to digest chitin; nine isolates have positive result of IAA-producing test; and five isolates could solubilize phosphate in Pikovskaya’s agar. There were two isolates, B11 and B15, that gave positive result in three tests, those are on cellulolytic, phosphate solubilizing, and IAA producing test. Molecular identification of B11 showed that the isolate was similar to Bacillus altitudinis (100%) and B15 was closed to Klebsiella oxytoca (99.73%).

Molecular Characterization of Four Alkaline Chitinases from Three Chitinolytic Bacteria Isolated from a Mudflat.

Four chitinases were cloned and characterized from three strains isolated from a mudflat: Aeromonas sp. SK10, Aeromonas sp. SK15, and Chitinibacter sp. SK16. In SK10, three genes, Chi18A, Pro2K, and Chi19B, were found as a cluster. Chi18A and Chi19B were chitinases, and Pro2K was a metalloprotease. With combinatorial amplification of the genes and analysis of the hydrolysis patterns of substrates, Chi18A and Chi19B were found to be an endochitinase and exochitinase, respectively. Chi18A and Chi19B belonged to the glycosyl hydrolase family 18 (GH18) and GH19, with 869 and 659 amino acids, respectively. Chi18C from SK15 belonged to GH18 with 864 amino acids, and Chi18D from SK16 belonged to GH18 with 664 amino acids. These four chitinases had signal peptides and high molecular masses with one or two chitin-binding domains and, interestingly, preferred alkaline conditions. In the activity staining, their sizes were determined to be 96, 74, 95, and 73 kDa, respectively, corresponding to their expected sizes. Purified Chi18C and Chi18D after pET expression produced N,N′-diacetylchitobiose as the main product in hydrolyzing chitooligosaccharides and colloidal chitin. These results suggest that Chi18A, Chi18C, and Chi18D are endochitinases, that Chi19B is an exochitinase, and that these chitinases can be effectively used for hydrolyzing natural chitinous sources.

Immobilization of Providencia stuartii Cells in Pumice Stone and Its Application for N-Acetylglucosamine Production.

SUMMARYResearch backgroundShrimp shells contain chitin that can be further processed into N-acetylglucosamine, which has been extensively used to treat joint damage. Providencia stuartii has a strong chitinolytic activity and may be utilized in the form of immobilized cells in repeated fermentation. Pumice is a porous and rigid stone that offers superior mechanical strength, making it suitable for immobilization.Experimental approachIn the research submerged fermentation with different pumice stone sizes and pumice stone/growth medium ratios (m/V) was carried out for 4 days at 37 °C and pH=7.0. The optimum pumice stone size and pumice stone/growth medium ratio (m/V) were used to determine the optimum fermentation cycle for the production of N-acetylglucosamine using immobilized P. stuartii.Results and conclusionsPumice stones of 1.0 cm×1.0 cm×1.0 cm and pumice stone/growth medium ratio of 1:5 were found to be the optimum conditions for successful immobilization of (90.0±1.6) % cells and production of (331.4±7.3) g/L N-acetylglucosamine. The highest N-acetylglucosamine concentration of (323.0±2.5) g/L was obtained in the first fermentation cycle, which then decreased and remained stable throughout the last three cycles.Novelty and scientific contributionP. stuartii, a strong chitinolytic bacterium previously isolated from rotten shrimp shells, was used for the first time in immobilized form to produce N-acetylglucosamine. The findings in this research showed the potential use of P. stuartii cells immobilized in pumice stone for continuous production of N-acetylglucosamine in repeated fermentation.

Effects of buffelgrass removal and nitrogen addition on soil microbial communities during an extreme drought in the Sonoran Desert

Buffelgrass (Cenchrus ciliaris), an invasive perennial grass in arid regions of the United States, has drastically modified natural ecosystems. Understanding the aboveground–belowground links between buffelgrass invasion and soil microbial communities will be critical for developing a comprehensive understanding of arid ecosystems and for deploying successful control strategies. In a randomized block‐field experiment located in Tucson, AZ, U.S.A., we investigated the effects of buffelgrass removal via hand pulling and nitrogen addition (and their interaction) on soil microbial communities during an extreme drought (summer 2020). We found that experimental treatments did not significantly impact bacterial and archaeal community diversity and composition, while plant removal affected fungal community diversity and composition. In addition, the removal treatment increased the proportion of putative chitinolytic bacteria (genus Lysobacter) and decreased the proportion of putative fungal endophytes (genus Darksidea). Buffelgrass manual removal appeared to favor fungal endophyte death around and inside of leftover intact roots, which may result in an increase of chitinolytic bacteria thriving on the degradation of fungal cell walls. Overall, our results suggest that hand removal—which is a common type of buffelgrass control—can alter soil fungal communities and the proportion of certain microbial functional groups. As these changes could subsequently affect native plants, more research is needed to develop a comprehensive understanding of the effect of buffelgrass control efforts on target plants as well as surrounding ecosystem dynamics.

Immobilization of Providencia stuartii Cells in Papaya Trunk Wood for N-acetylglucosamine Production from Pennaeus vannamei Shrimp Shells

Highlight Research AbstractChitin is a natural compound found abundantly in shrimp shells. Chitin can be degraded to produce N-acetylglucosamine, which has wide applications in the food and pharmaceutical fields. Fermentation using chitinolytic microorganisms can be used to produce N-acetylglucosamine from shrimp shells’ chitin. One of the strong chitinolytic bacteria that was isolated from previous research was Providencia stuartii. To provide better stability and efficiency in fermentation, P. stuartii cells were immobilized using entrapment method in papaya trunk wood. The aims of this research were to determine the optimum papaya trunk wood size, ratio of papaya trunk wood and growth medium, as well as the optimum fermentation cycle to produce N-acetylglucosamine from P. vannamei shrimp shells using submerged fermentation method. The research used experimental method with treatment of different sizes of papaya trunk wood (1 x 1 x 1 cm3, 1.5 x 1.5 x 1.5 cm3, and 2 x 2 x 2 cm3), different ratio of papaya trunk wood and growth medium (1:10, 1:15 and 1:20), and 4 fermentation cycles. Results showed that papaya trunk wood with size of 1 x 1 x 1 cm3 and ratio (w/v) of 1:10 could immobilize 87.08±2.05% of P. stuartii cells and produce the highest N-acetylglucosamine concentration, which was 238177.78±3153.48 ppm. The highest N-acetylglucosamine production was obtained from first fermentation cycle and decreased over the last three cycles, but still produced high concentration of N-acetylglucosamine. Therefore, it is possible to perform continuous N-acetylglucosamine production from shrimp shells using P. stuartii cells immobilized in papaya trunk wood.

Isolation and antagonism of chitinolytic bacteria from Ipomea pes caprae against Lasiodiplodia pseudotheobromae

Chitin is the main component of fungal cell walls. The growth of fungi can be inhibited by chitinolytic bacteria because they can produce chitinase enzymes which play a role in degrading cell walls. The purpose of this study was to test the activity of bacteria isolated from the roots of Ipomea pes caprae in inhibiting the growth of the fungus Lasiodiplodia pseudothebromae. The research method was carried out by isolating as much as 5 g of I. pes caprae roots using specific media and testing for bacterial antagonism using a dual culture method. The results showed that there were four isolate codes obtained namely IPaR1, IPaR4, IPpA2, and IPpA3 and could inhibit the growth of Lasiodiplodia pseudtheobromae.

Genomic and Proteomic Study of Andreprevotia ripae Isolated from an Anthill Reveals an Extensive Repertoire of Chitinolytic Enzymes.

Chitin is an abundant natural polysaccharide that is hard to degrade because of its crystalline nature and because it is embedded in robust co-polymeric materials containing other polysaccharides, proteins, and minerals. Thus, it is of interest to study the enzymatic machineries of specialized microbes found in chitin-rich environments. We describe a genomic and proteomic analysis of Andreprevotia ripae, a chitinolytic Gram-negative bacterium isolated from an anthill. The genome of A. ripae encodes four secreted family GH19 chitinases of which two were detected and upregulated during growth on chitin. In addition, the genome encodes as many as 25 secreted GH18 chitinases, of which 17 were detected and 12 were upregulated during growth on chitin. Finally, the single lytic polysaccharide monooxygenase (LPMO) was strongly upregulated during growth on chitin. Whereas 66% of the 29 secreted chitinases contained two carbohydrate-binding modules (CBMs), this fraction was 93% (13 out of 14) for the upregulated chitinases, suggesting an important role for these CBMs. Next to an unprecedented multiplicity of upregulated chitinases, this study reveals several chitin-induced proteins that contain chitin-binding CBMs but lack a known catalytic function. These proteins are interesting targets for discovery of enzymes used by nature to convert chitin-rich biomass. The MS proteomic data have been deposited in the PRIDE database with accession number PXD025087.

Genome analysis of Streptomyces sp. UH6 revealed the presence of potential chitinolytic machinery crucial for chitosan production.

Chitosan and its derivatives have numerous applications in wastewater treatment as bio-coagulants, flocculants and bio-adsorbents against both particulate and dissolved pollutants. Chitinolytic bacteria secrete an array of enzymes, which play crucial role in chitin to chitosan conversion. Consequently, there is a growing demand for identification and characterization of novel bacterial isolates with potential implications in chitosan production. We describe genomic features of the new isolate Streptomyces sp. UH6. Analysis of the 6.51 Mb genome revealed the GC content as 71.95% and presence of 6990 coding sequences of which 63% were functionally annotated. Further, we identified two possible chitin-utilization pathways, which employ secreted enzymes like lytic polysaccharide monooxygenases and family-18 glycoside hydrolases (GHs). More importantly, the genome has six family-4 polysaccharide deacetylases with probable role in chitin to chitosan conversion, as well as two chitosanases belonging to GH46 and GH75 families. In addition, the gene clusters, dasABC and ngcEFG coding for transporters, which mediate the uptake of N,N'-diacetylchitobiose and N-acetyl-d-glucosamine were identified. Several genes responsible for hydrolysis of other polysaccharides and fermentation of sugars were also identified. Taken together, the phylogenetic and genomic analyses suggest that the isolate Streptomyces sp. UH6 secretes potential chitin-active enzymes responsible for chitin to chitosan conversion.

Gut microbiome alterations in the crustacean Pacifastacus leniusculus exposed to environmental concentrations of antibiotics and effects on susceptibility to bacteria challenges

Gut-associated microbiota in crustaceans are recognized as a key element for maintaining homeostasis and health in the animal. Since the richness of these microbial communities is strongly influenced by the local environment, especially in aquatic organisms, it is important to address to what extent environmental variations can affect these communities. In the present study, we used high-throughput 16S rRNA sequencing technology to study the composition of gut-associated microbiota of the crayfish Pacifastacus leniusculus after exposure to environmentally-relevant concentrations of an antibiotic, namely sulfamethoxazole. Also, we examined if alterations of microbiota caused by environmentally-relevant concentrations of this antibiotic affected the host susceptibility to bacterial diseases, including Vibrio species. As a result, we found high individual variability of bacterial abundance and composition in the intestinal microbiome of crayfish, in both antibiotic-exposed and antibiotic-free crayfish. However, an increase of chitinolytic bacteria including Vibrio spp. was detected in some animals exposed to the antibiotic. Moreover, when crayfish susceptibility to bacterial infections was tested, the antibiotic-exposed crayfish survived longer than the control crayfish group. This study represents the first approach for investigating the interplay between crayfish and intestinal bacteria during antibiotic-pollution scenarios. Results herein should be considered by scientists before planning experiments under laboratory conditions, especially to study environmental effects on aquatic animals' intestinal health and immune status.

Extracellular Antifungal Activity of Chitinase-Producing Bacteria Isolated From Guano of Insectivorous Bats.

A reduction in the use of agrochemicals requires the development of either alternatives or complementary control methods in order to limit their dangerousness. An alternative is the biological control of fungi by bacteria. The fungal cell wall is a unique structure of the fungi, composed of glucan, chitin, and glycoproteins. Therefore, bacteria producing mycolytic enzymes, like chitinases, are of great interest to degrade fungal cell-wall components. The objectives of this work were to isolate chitinolytic bacteria from the guano of insectivorous bats (Tadarida brasiliensis) and to verify the presence of antifungal activities against phytopathogenic fungi. From the guano samples, 28 bacterial isolates were obtained, 70% of which presented chitinolytic activity. Four isolates were selected since they showed the highest values of chitinase activity, and they were characterized as belonging to Bacillus genus, by analyzing the 16S ribosomal RNA gene sequence. Cell-free supernatants of bacterial cultures were used in inhibition tests on 16 fungi: Alternaria and Colletotrichum acutatum were the most affected. Chitinase and antifungal activities were observed in the cell-free supernatant regardless of the culture medium used. Both activities were stable to heat and proteinase K treatments. Finally, when the culture medium was supplemented with 1ml of cell-free supernatants (0.33%) and incubated for 120h, the inhibition of hyphae formation and germination spores of reporter fungus were observed under light microscopy. These results suggest the feasibility of using cell-free supernatants as eco-friendly fungicides. The use of them may contribute to reducing the dose of toxic chemicals.

Induction of gene expression and chitinolytic activities of putative chitinase gene bacteria Serratia plymuthica UBCF_13

The most dominant disease that causes low production of chili in Indonesia is anthracnose. Anthracnose disease is caused by the pathogenic fungi called Colletotrichum sp. The control of anthracnose disease can be done by using bio fungicides which can be developed from the class of enzymes that degrade pathogenic fungal cell walls. These enzymes are known as hydrolase enzymes, one of which is Chitinase. Chitinase is an enzyme that catalyzes the breakdown of chitin polymer compounds in β-1,4 glycosidic bonds. Chitin is a polymer compound that makes up the fungal cell wall. Chitinolytic bacteria can produce chitinase enzymes. S. plymuthica bacteria produce chitinase enzyme, one of which is putative chitinase [Chi_Put]. The purpose of this study was to express the Chi_Put gene from S. plymuthica UBCF_13 in pGEM-T Easy vector using Escherichia coli BL21 and to test the chitinolytic activity of Chi_Put in degrading chitin in-vitro. Chi_Put gene expression was induced by IPTG and in combination with Mg2+ and Cu2+ metal ions. The highest gene expression was marked by the thickest protein band on the SDS-PAGE visualization with a molecular weight of 47 kDa, namely in the treatment of expression induction with IPTG plus Mg2+ metal ion. The chitinolytic activity of Chi_Put UBCF_13 was tested using solid LB media containing 3% colloidal chitin. The longest clear zone diameter on the last day of observation was the expression induction treatment with Mg2+ with a length of 2.90 cm.

Characterization of the gene encoding chitinase enzyme from bacillus isolates insulated from some locations in Southeast Sulawesi

This study aimed to determine the isolates of local Bacillus that have potential chitinolytic activity and to know the characteristic of the gene encoding chitinase enzyme from local Bacillus isolates from Southeast Sulawesi that were selected to have chitinolytic activity. Selection of chitinolytic bacteria based on bacterial ability to form clear zone on chitin agar medium which was grew by spread method and incubated for 4 days. From 5 test isolates used, one isolate which had chitinolytic activity was isolate Bacillus sp. Rh 3.8. The amplification of the gene encoding chitinase enzyme selected bacterial isolates was done by PCR (Polymerase Chain Reaction) technique using Chitbac F and Chitbac R primers. Sequence analysis was conducted by BLASTn, mapping of restriction enzyme using Bioedit software, analysis of amino acid using expasy software, analysis of hydrophobicity using Bioedit software, phylogenetic tree construction using MEGA software. The results showed that the characters of the gene encoding chitinase enzyme was a gene measuring 804 bp. Based on BLASTn analysis, the gene has 100% similarity with Bacillus thuringiensis SCG0402 (CP017577). The gene has 9 restriction enzyme cutting sites. Based on hydrophobicity analysis shows that the amino acid sequence of chitinase enzyme is dominant exist on hydrophilic region. The results of phylogenetic tree construction show isolates of the Bacillus sp. Rh 3.8 is a group with Bacillus thuringiensis so this strain is a species of Bacillus thuringiensis.

Novel chitinolytic bacteria from the shrimp shell processing waste

Abstract. Masri M, Sukmawaty E, Aditia L. 2021. Novel chitinolytic bacteria from the shrimp shell processing waste. Biodiversitas 22: 2672-2681. Chitinase is an enzyme that hydrolyzes chitin (?-1,4 Nsetyl-D-glucosamine polymer). Several types of microorganisms produce chitinase that contributes to basic science and application. The role of chitinase enzyme is widely utilized in various fields, such as health as an anti-tumor agent and agriculture as biological control agents in plant disease caused by fungus. The purpose of this study was to isolate novel chitinolytic bacteria from shrimp shell waste in Makassar, Indonesia, using the scatter plate method on chitin agar selective media incubated at 37°C for 3 days. The clear zone formation around the colony was marked as an indicator of chitinase activity performed by the certain isolate. Selection was carried out by recycling all isolates on chitin agar media, which were incubated at 37°C for 3 days and measured the chitinolytic index. Two of ten isolates produced the highest chitinolytic index, namely, KLA-2 (45) and KLA-4 (15) isolates. The molecular identification results showed that the KLA-2 and KLA-4 isolates were Lysinibacillus fusiformis strain WH22 and Brevibacillus reuszeri strain CMB-15, respectively. Therefore, novel chitinolytic bacteria that can produce chitinase enzyme from shrimp shell waste are L. fusiformis and B. reuszeri

Bioconversion of Shrimp Shell Waste into Compost Preparation and its Plant Growth Study

Background: The fishing sector plays an important role in the global economy. The development of this sector is related to environmental issues, in particular to waste management. Indeed, the quantity of the halieutic waste are considered at several thousand tons of waste a year. Waste management is a solution to maintain an area with ecological harmony, but still can produce economic benefits that are beneficial to social welfare. Chitinases are enzymes that degrade chitin. Chitinase contribute to the generation of carbon and nitrogen in the ecosystem from shrimp shell wastes. Chitin and chitosan are naturally-occurring compounds that have potential to be used in agriculture. The present study was designed to prepare the shrimp shell waste compost (SSC) and also to analyse the enhancement growth of Ladies finger plant by using shrimp shell waste compost (SSC), shrimp shell waste compost (SSC) +cow dung (CD) and along with coir pith (CP).Methods: This experiment was conducted within the period of 2017-2018 in Department of Microbiology, Kamaraj college, Thoothukudi. 1Kg of dried shrimp shell waste powder was used for the compost preparation using chitinolytic bacteria Bacillus licheniformis SSCL10. The present study shrimp shell wastes were composted into manure with adding chitinolytic Bacillus licheniformis SSCL10. After 90 days of composting, the compost was dried at room temperature and used as manure for plant study. The growth study of ladies finger (Abelmoschus esculents L.) was analyzed in shrimp shell compost and also along with other composts (SSC + CD and SSC + CD+CP).Result: In our study, nitrogen, phosphorus and potash content were increased in the shrimp shell composts (SSC) with adding chitinase producing bacterium (Bacillus licheniformis SSCL10) when compared with control soil. The maximum plant growth performances were showed in the SSC+CD (cow dung) compared to combination of CP (coir pith), shrimp shell composts (SSC) alone and control. So shrimp shell compost is used as supplements for other compost to induce plant growth performances.

The Potency of UB Forest Chitinolytic Bacteria to Promote Plant Growth and Inhibit Damping off Disease on Soybean

Damping off disease in soybean plants is caused by the fungal Rhizoctonia solani. The damping off disease causes a yield loss of up to 85-100%. The purpose of this study was determining the ability chitinolytic bacteria consortium of UB Forest's in suppressing damping off disease in vitro and in vivo as well as its potential to stimulate the growth of soybean plants. The research stages included isolation of the pathogenic fungus R. solani and the pathogenicity test. Rejuvenation chitinolytic bacterial isolates of UB Forest, test chitinolytic bacteria antagonist of UB Forest against R. solani fungus, test of Plant Growth Promoting (PGP) activities, synergy test of selected chitinolytic bacterial isolates, in vitro test for the inhibition of chitinase crude extract against R. solani, and inhibition test of chitinolytic bacteria consortium against damping off disease. The selected chitinolytic bacteria were code bacteria UB12, UB19, and UB52 with plant growth promoting activities with inhibition percentage of the pathogen R. solani of 73.9%, 67.4%, and 71.7%. The best chitinolytic bacterial isolates were the genus Bacillus sp. and Pseudomonas sp. The inhibition test of chitinase crude extract showed an inhibition percentage of 25-55%.

Structures and functions of carbohydrate-active enzymes of chitinolytic bacteria Paenibacillus sp. str. FPU-7.

Chitin and its derivatives have valuable potential applications in various fields that include medicine, agriculture, and food industries. Paenibacillus sp. str. FPU-7 is one of the most potent chitin-degrading bacteria identified. This review introduces the chitin degradation system of P. str. FPU-7. In addition to extracellular chitinases, P. str. FPU-7 uses a unique multimodular chitinase (ChiW) to hydrolyze chitin to oligosaccharides on the cell surface. Chitin oligosaccharides are converted to N-acetyl-d-glucosamine by β-N-acetylhexosaminidase (PsNagA) in the cytosol. The functions and structures of ChiW and PsNagA are also summarized. The genome sequence of P. str. FPU-7 provides opportunities to acquire novel enzymes. Genome mining has identified a novel alginate lyase, PsAly. The functions and structure of PsAly are reviewed. These findings will inform further improvement of the sustainable conversion of polysaccharides to functional materials.

Recent advances in the bioprospection and applications of chitinolytic bacteria for valorization of waste chitin.

One of the most abundant natural polymers on earth, chitin is a fibrous and structural polysaccharide, composed of N-acetyl-D-glucosamine. The biopolymer is the major structural constituent of fungi, arthropods, mollusks, nematodes, and some algae. The biodegradation of chitin is largely manifested by chitinolytic enzyme secreting organisms including bacteria, insects, and plants. Among them, bacterial chitinases represent the most promising, inexpensive, and sustainable source of proteins that can be employed for industrial-scale applications. To this end, the presented review comes at a timely moment to highlight the major sources of chitinolytic bacteria. It also discusses the potential pros and cons of prospecting bacterial chitinases that can be easily manipulated through genetic engineering. Additionally, we have elaborated the recent applications of the chitin thereby branding chitinases as potential candidates for biorefinery and biomedical research for eco-friendly and sustainable management of chitin waste in the environment.

Isolation and identification of proteolytic, amylolytic, lipolytic, and chitinolytic bacteria from shrimp waste

Bacteria and microbial enzymes are biocatalysts and can be used as an alternative to industrial chemical processes. The present study focused on isolating and identifying bacterial strains from shrimp waste, that produce amylases, lipases, proteases and chitinases with potential use on shrimp waste treatment. Thirty-two bacterial strains were isolated, phenotypically characterized, and identified by the API system and the molecular analysis of the 16S rDNA. It was found that 28.13% of the isolated bacterial strains had amylolytic capacity, 87.50% lipolytic, 96.88% proteolytic and 28.13% chitinolytic capacity on agar plates with specific substrates. The genera Bacillus, Burkholderia, Ochrobactrum, Vibrio, Pseudomonas and Shewanella were identified. Bacteria with enzymatic capacities isolated in the present study, could be used to obtain by-products from shrimp waste as well as other industrial applications.

Control of Banana Wilt Disease Caused by Fusarium oxysporum Schlecht f.sp. cubense (E. F. Smith) Using Crab Shell Powder and Chitosan

This research was conducted to evaluate the effectiveness of crab shell powder and chitosan to control Fusarium wilt disease on bananas and to analyze the involved control mechanisms. The effectiveness of crab shell powder and chitosan to F. oxysporum f.sp. cubense was examined in a laboratory (in vitro) and greenhouse (in planta). In vitro evaluation showed that chitosan has an antifungal effect while crab shell powder did not. Application of crab shell powder and chitosan suppressed the disease in green house test. The concentrations of crab shell powder and chitosan that most effective to control Fusarium wilt incidences were 0.25% and 0.10% with an efficacy rate of 66.7% and 83.3%, respectively. The highest disease severity reduction was showed by crab shell powder 0.25% and chitosan 0.50% with an efficacy rate of 56.8% and 59.4%, respectively. Suppression of the disease might be due to the fungicidal effect of chitosan and the increase of the total population of bacteria and chitinolytic bacteria in the rhizosphere when banana seedling roots were treated with crab shell powder or chitosan. Experiment results using the split roots technique exhibited the role of crab shell powder and chitosan potentially to induce the resistance of banana to Fusarium wilt.

Chitinase activity potential and identification of chitinolytic bacteria isolated of swimmer crab’s cell

This study aimed at investigating the chitinase enzyme activity produced by chitinolytic bacteria from the skin of blue swimmer crab (Portunus pelagicus) and identification of the genus isolate. This study consists of two stages: firstly, the qualitative and quantitative activity of the chitinase enzyme; and secondly, biochemical identification of the bacteria. The quantitative chitinase enzyme activity is measured using the UV-Vis spectrophotometer UV-Vis at the wavelength at 660 nm. The chitinase enzyme is obtained from the isolation of chitinolytic bacteria cultured within a media to grow solid chitin, which contains colloidal chitin substrate as chitinase inductor at the temperature of 30°C. The highest chitinolytic activity is obtained from the 24 h supernatant culture, with a value of enzyme activity at 0.149 U/mL. Macroscopic and microscopic identification showed that the chitinolytic bacteria isolate R1, whereas the biochemical cell shows the characteristics of the genus Pseudomonas. Keywords: biodegradable, chitinase, spectrophotometer, Portunus pelagicus, Pseudomonas DOI: 10.25165/j.ijabe.20211403.5273 Citation: Sulistijowati R, Sudin, Harmain R M. Chitinase activity potential and identification of chitinolytic bacteria isolated of swimmer crab’s cell. Int J Agric & Biol Eng, 2021; 14(3): 228–231.