Cellulase enzyme activity of the bacteria isolated from mangrove ecosystem in Aceh Besar and Banda Aceh

Cellulolytic bacteria is one of the beneficial bacteria that can found in mangrove ecosystem. The purposes of study were to analyse the cellulolytic index, and to analyse the cellulase activity of bacteria isolated from soil mangrove. Qualitatively, assessment of cellulase activity were carried out at the Microbiology laboratory of Fish Quarantine Station, Quality Control and Safety of Fishery Products (SKIPM) Aceh, while quantitatively was observed in microbiology laboratory, Biology Department, IPB. Assessment of qualitative cellulase activity is performed by growing the selected pure isolate on 1% CMC medium then spilled 1% congo red to test its cellulolytic potential. Cellulolytic potential was determined by clear zone performed around the colony after congo red flooded. The quantitative cellulase enzyme activity test carried out by DNS method tested on one selective isolate. There were 21 from 39 isolates showed a clear zone isolated from mangrove soil. The cellulolytic index (CI) obtained ranged from 0.07 to 0.80 classified as low cellulolytic index criteria. The cellulolytic index was higher in bacteria isolated from mangrove rehabilitated than mangrove unrehabilitated. The highest cellulase activity and specific cellulase activity of BTMD32 was at 48 hours with the value were 0.0012 U/ml, 0.077 U/mg, respectively. The result concluded that the bacteria cellulolytic isolated from mangrove soil had low cellulolytic index, low cellulase activity, and low specific cellulase activity.

Metabolomics Tools Assisting Classic Screening Methods in Discovering New Antibiotics from Mangrove Actinomycetia in Leizhou Peninsula

Mangrove actinomycetia are considered one of the promising sources for discovering novel biologically active compounds. Traditional bioactivity- and/or taxonomy-based methods are inefficient and usually result in the re-discovery of known metabolites. Thus, improving selection efficiency among strain candidates is of interest especially in the early stage of the antibiotic discovery program. In this study, an integrated strategy of combining phylogenetic data and bioactivity tests with a metabolomics-based dereplication approach was applied to fast track the selection process. A total of 521 actinomycetial strains affiliated to 40 genera in 23 families were isolated from 13 different mangrove soil samples by the culture-dependent method. A total of 179 strains affiliated to 40 different genera with a unique colony morphology were selected to evaluate antibacterial activity against 12 indicator bacteria. Of the 179 tested isolates, 47 showed activities against at least one of the tested pathogens. Analysis of 23 out of 47 active isolates using UPLC-HRMS-PCA revealed six outliers. Further analysis using the OPLS-DA model identified five compounds from two outliers contributing to the bioactivity against drug-sensitive A. baumannii. Molecular networking was used to determine the relationship of significant metabolites in six outliers and to find their potentially new congeners. Finally, two Streptomyces strains (M22, H37) producing potentially new compounds were rapidly prioritized on the basis of their distinct chemistry profiles, dereplication results, and antibacterial activities, as well as taxonomical information. Two new trioxacarcins with keto-reduced trioxacarcinose B, gutingimycin B (16) and trioxacarcin G (20), together with known gutingimycin (12), were isolated from the scale-up fermentation broth of Streptomyces sp. M22. Our study demonstrated that metabolomics tools could greatly assist classic antibiotic discovery methods in strain prioritization to improve efficiency in discovering novel antibiotics from those highly productive and rich diversity ecosystems.

Antimicrobial and Antioxidant Activities of Streptomyces sps Isolated from Muthupettai Mangrove Soil

Muthupet mangrove forest soil sediment was the abundant resource of the actinomycetes with distinct nature of bioactive compounds. The soil sediment was collected at 1-3meter away from bank. The present study was focused on isolation, identification and antimicrobial activity of the actinomycetes from Muthupet mangrove soil samples. Totally 32 actinomycetes strains was isolated and screened for antimicrobial activity against bacterial and fungal pathogens. Among 32 isolates 16 have antibacterial activity and 10 have antifungal activity but MG-3 and MG-4 showed maximum activity against both all the test pathogens. These two strains are gram-positive, rod-shaped, MG-3 possessing an earthy characteristic odour and MG-4 produce purple color pigment. The isolates were confirmed as Streptomyces sp. based on morphological, cultural, biochemical and physiological observations, as well as identification using the 16S rRNA gene sequence, it showed 98% similarity with Streptomyces parvus for MG-3 and Streptomyces californicus for MG-4. Bioactive compounds were extracted from Streptomyces using different solvents such as ethyl acetate, methanol, chloroform, hexane and antibacterial activities were assayed against test pathogens, ethyl acetate extract showed maximum zone of inhibition when compared with other solvents. The Minimum inhibitory concentration of ethyl acetate extract was found ranged between 1.96-3.9 μg/ml. The invitro antioxidant capacity of the crude extract was estimated by DPPH, ferric reducing power assay, H202 radical scavenging assay, phosphomolybdenum assay and total antioxidant activities. The characterization of crude extracts was analyzed by FTIR and GC-MS. From the results, it is clear that the ethyl acetate crude extract of S.parvus MG-3 and S.californicus MG-4 possesses high antimicrobial and antioxidant activity and suggested that the isolated strains could be a potential for the nature resource of pharmaceutical.

Recent Nitrogen Storage and Accumulation Rates in Mangrove Soils Exceed Historic Rates in the Urbanized San Juan Bay Estuary (Puerto Rico, United States)

Tropical mangrove forests have been described as “coastal kidneys,” promoting sediment deposition and filtering contaminants, including excess nutrients. Coastal areas throughout the world are experiencing increased human activities, resulting in altered geomorphology, hydrology, and nutrient inputs. To effectively manage and sustain coastal mangroves, it is important to understand nitrogen (N) storage and accumulation in systems where human activities are causing rapid changes in N inputs and cycling. We examined N storage and accumulation rates in recent (1970 – 2016) and historic (1930 – 1970) decades in the context of urbanization in the San Juan Bay Estuary (SJBE, Puerto Rico), using mangrove soil cores that were radiometrically dated. Local anthropogenic stressors can alter N storage rates in peri-urban mangrove systems either directly by increasing N soil fertility or indirectly by altering hydrology (e.g., dredging, filling, and canalization). Nitrogen accumulation rates were greater in recent decades than historic decades at Piñones Forest and Martin Peña East. Martin Peña East was characterized by high urbanization, and Piñones, by the least urbanization in the SJBE. The mangrove forest at Martin Peña East fringed a poorly drained canal and often received raw sewage inputs, with N accumulation rates ranging from 17.7 to 37.9 g m–2 y–1 in recent decades. The Piñones Forest was isolated and had low flushing, possibly exacerbated by river damming, with N accumulation rates ranging from 18.6 to 24.2 g m–2 y–1 in recent decades. Nearly all (96.3%) of the estuary-wide mangrove N (9.4 Mg ha–1) was stored in the soils with 7.1 Mg ha–1 sequestered during 1970–2017 (0–18 cm) and 2.3 Mg ha–1 during 1930–1970 (19–28 cm). Estuary-wide mangrove soil N accumulation rates were over twice as great in recent decades (0.18 ± 0.002 Mg ha–1y–1) than historically (0.08 ± 0.001 Mg ha–1y–1). Nitrogen accumulation rates in SJBE mangrove soils in recent times were twofold larger than the rate of human-consumed food N that is exported as wastewater (0.08 Mg ha–1 y–1), suggesting the potential for mangroves to sequester human-derived N. Conservation and effective management of mangrove forests and their surrounding watersheds in the Anthropocene are important for maintaining water quality in coastal communities throughout tropical regions.

Antibacterial Screening of Bacterial Isolates Associated with Mangrove Soil from the Ngurah Rai Mangrove Forest Bali

In this study we reported cultivation of bacteria associated with mangrove soil from the Ngurah Rai Mangrove Forest, Bali. Mangrove soil samples were serially diluted using sterile artificial seawater, spread onto Starch Casein M agar and incubated at 28oC for 28 days. Cultivation of mangrove soil samples yielded 165 bacterial colonies with 68 isolates were selected and purified based on different morphology. Of these 68 isolates, 22 isolates displayed antibacterial activities ranging from weak to strong inhibition against at least one of four bacterial indicators namely Staphyloccocus aureus, Streptococus mutans, Escherichia coli and Klebsiella pneumoniae using perpendicular streak method. Overall, 19 out of 22 bacteria isolates displayed weak antibacterial potential and two isolates exhibited moderate antibacterial activity. The isolate SA4 was the only bacterium with strong antibacterial potential with measured clear distance ≥ 10 mm against the four bacterial isolates. Sequence analysis based on 16S rRNA gene fragment assigned the isolate SA4 as Bacillus subtilis strain BIL/BS-168. Overall, this study confirmed the untapped potential of antibacterial activities from bacteria associated with mangrove soil.

Morphological identification of phosphate solubilizing and cellulolytic fungi from mangrove soil under Rhizophora stylosa stands

Mangrove forest is one of the forest ecosystems that can be found in tidal areas. Mangrove forest have ecological, socio-economic benefits for organisms that live in the sea. One of the microorganism that live in mangrove forest is fungus. Therefore, this study aimed to isolate and identify phosphate solubilizing and cellulolytic fungi from mangrove soil. Soil samples were collected from a stands of Rhizophora stylosa in Lubuk Kertang Village, West Brandan District, Langkat Regency, North Sumatra. Soil samples were taken randomly with a dept of 0-20 cm. Isolation of phosphate solubilizing fungi was carried out using Pikovskaya medium and cellulolytic fungi using carboxyl methyl cellulose (CMC) medium. To determine the effectiveness of fungi qualitatively, the phosphate solubility and cellulolytic index were calculated. All isolates obtained were identified morphologically by observing colonies macroscopically and microscopically. This study obtained 12 isolates of phosphate solubilizing and 8 isolates of cellulolytic fungi. Phosphate solubility index ranging from 2.06-2.87 and cellulolytic index of 0.33-3.00. Morphological identifications showed that all isolates of phosphate solubilizing fungi belonged to the genus Aspergillus, while all isolates of cellulolytic fungi belonged to the genus Chaetomium.

Isolation, Selection and Antimicrobial Activity of Actinomycetes from Mangrove Soil of Can Gio Forest, Hochiminh City, Vietnam

The Can Gio Mangrove is a Biosphere Reserve of UNESCO since 2000 and it is also a well-known example of “mangrove afforestation and reforestation area’’. A total of 63 actinomycetes were isolated from 25 samples of 9 different sites in mangrove forest soil Can Gio, HoChiMinh city, Vietnam. Almost their colonies have round-shaped; milky, white clear and yellow, entire or loabate margin; diameter size of these colonies varied from 0.2 to 3.0 mm. Twenty-nine of 63 tested isolates could produce antimicrobial active metabolites inhibiting at least one of the tested pathogens and 9 isolates were selected for 16S rDNA sequencing. The result showed that genus Streptomyces (8 isolates) and other genera including 1 isolates were Gram-negative bacteria (Stenotrophomonas). The antimicrobial activity and the amplifying genes coding for polyketide synthetase (PKS) and nonribosomal peptide synthetase (NRPS) showed that 8 strains had broad-spectrum antimicrobial activity, mainly against gram-positive bacteria as Bacillus cereus and Staphylococcus aureus.