Peatlands are terrestrial wetland ecosystems formed from piles of organic matter that decompose into organic deposits. Peat soil has a high potential to produce cellulose which, can be reused by cellulolytic bacteria. This study aims to find out the potential strain of cellulolytic bacteria isolated from peatland ecosystems. The method used was experimental, sequentially, the stages are isolation and screening for cellulolytic bacteria, quantitative testing of cellulolytic activity, characterizing the morphology and physiology of bacteria, and the identification of bacteria based on Bergey’s Manual of Determinative Bacteriology. The screening results obtained seven isolates of cellulolytic bacteria capable of hydrolysed cellulose on 1% Carboxy Methyl Cellulose (CMC) Agar Medium, namely SPS1, SPS2, SPS 3, SDG1, SDG 2, SPW1, and SPW4. Three of seven isolates obtained the highest cellulolytic index sequentially, namely SPS2 of 2.82, SPS3 of 2.65, and SDG1 of 2.47. The cellulolytic activity was indicated by the value of a halo zone around the colonies on 1 % CMC medium after being dripped with Congo red. The halo zone is an early indication to determine the ability of bacteria to decompose cellulose. Based on Bergey’s Manual of Determinative Bacteriology showed that the three isolates had the same characteristics as the genus Bacillus, Lactobacillus and Corynebacterium.

Marine bacteria including heterotrophic bacteria are the most numerous organisms in nature and are capable of producing secondary metabolites. The secondary metabolite produced is a molecular compound produced from the secondary metabolic process, generally can be in the form of antibiotics, enzyme inhibitors, toxins, growth regulators, hormones, and insecticides. This study aims to examine the inhibitory ability of secondary metabolites of heterotrophic bacteria to the activity of pathogenic bacteria Aeromonas hydrophilla, Pseudomonas aeruginosa, and Vibrio alginolyticus. Around 10 heterotrophic bacterial isolates from the Marine Microbiology Laboratory collection, Fisheries and Marine Sciences Faculty, University of Riau was tested on pathogenic bacteria based on the Kirby-Bauer disk diffusion method. The results showed that all heterotrophic bacterial isolates were capable of inhibiting the growth of pathogenic bacteria such as A. hydrophilla (P), P. aeruginosa (Q), and V. alginolyticus (R). Vagococus fluvialis isolates are the best heterotrophic bacterial isolates in producing secondary metabolites compared to 9 other isolates. Where the clear zone formed is wider, that is 12.35 mm with the results of the activity test of 1877.78 mm2/ml. Based on the results, the heterotrophic bacteria are capable of producing secondary metabolites that inhibit the growth of pathogenic bacteria.

A survey of marine bivalves for species diversity was conducted at five locations in the current study; Three stasiun at Dumai city beach those are Silensing, Bandar Bakau, Basilam Baru, Sri Tanjung, and Pulau Payung beach of Rupat Island Strait, Riau Povince. Indonesia. The goal of this study was to learn more about the marine bivalves that live in the Rupat Island strait. From July to August 2020, marine bivalves were collected during spring low tides from intertidal zones and shallow coastal waters. From the Strait of Rupat Island, 13 bivalves belonging to 11 genera, 11 families and 8 orders were discovered. During the research, bivalves from the families Pectinidae, Placunidae, Arcidae, Trapezidae, Veneridae Ostreidae, Corbiculidae, and Psammobiidae were recorded during the study. The number of bivalves in each family reveals that two species belongs to the Arcidae family and two to the Cyrenidae family. Corbiculidae, Placunidae, Trapezidae, and Psammobiidae each had one species reported. The abundance of each species found was extremely low, it is not feasible to be presented quantitatively. The most common species encountered in the strait were Anadara granosa, Polymesoda erosa, Polymesoda expansa, and Pharella acutidens. The anthropogenic activities of Dumai city and Rupat Island, such as the discharge of industrial wastes, residential sewage, overfishing, habitat loss, overharvesting and tourism, could cause variations in bivalves abundance in the Strait of Rupat Island.

The presence of pathogenic bacteria in shrimp culture water could influence the shrimp growth and production. This research aimed to quantify total coliform, Escherichia coli and total Vibrio in pond water of Vannamei shrimp (Litopenaeus vannamei) culture in Rupat Island. Water samples from inlet water (IW), water from three ponds (PW2, PW3, PW6) and outlet water (OW) were collected for the quantification of total coliform and Escherichia coli by the MPN technique and total Vibrio count on TCBS agar. Coliforms was found in all water samples, the lowest count was in inlet water sample (20 MPN/100 mL), and the highest was contained in outlet water (>2400 MPN/100 mL), however E. coli was not detected in all water samples. Meanwhile, the lowest total Vibrio count was found in PW3 (6.35 × 103), and the highest was in the PW6 (3.10 × 105). In addition to the microbiological quality, some water quality parameters were also observed, those were water temperature in the range of 27.5- 29.4°C, salinity of 18.7-21.5 ppt, pH of 7.17-7.89, DO of 1.3-7.6 mg/L, NH3 content of 0.96-1.26 mg/L and DOM of 26.2–27.6 mg/L. The data indicated that pathogenic bacteria were present in all pond waters which should be decreased for the safety shrimp production.

Belulang grass (Eleusine indica) is a plant in the Poaceae family that is commonly found in the coastal area of Dumai, Riau Province. Eleusine indica is characterized by narrow leaves, concave stems that can reach up to 95 cm high and strong roots. E. indica is known to be very tolerant of its environment, including the environment contaminated with heavy metals. The ability of E. indica as a phytoremediation agent in absorbing heavy metals has been widely known as the role of metallothionein (MT) protein. MT is believed to have a function in the metal metabolism and detoxification process through the metal chelating interaction between the cysteine amino acid residues. This unique function prompted the interest to isolate the MT gene from E. indica. This method involves the isolation of genomic DNA from E. indica followed by the process of amplification of the MT gene using specific primers, namely MTFS and MTRS by polymerase chain reaction (PCR) technology. The success of the MT gene isolation process from E. indica was evidenced by the presence of a single band size of around 172 bp via the visualization process on 1% agarose gel. Furthermore, the results of the PCR product are purified for the purpose of sequencing activity. The results of sequencing analysis of the 172 bp fragment showed 99.31% identical similarity with the complete metallothionein gene from E. indica (DQ082855.1) by using the BLASTN tool, NCBI website.