Exploration and Molecular Identification of Proteolytic Bacteria as Probiotic Candidates from Shrimp Ponds in West Sumatra, Indonesia.

<b>Background and Objective:</b> The existence of intensive shrimp aquaculture faces serious challenges in the form of a decrease in pond water quality due to overfeeding. Efforts are needed to improve pond water quality by utilizing proteolytic bacterial isolates to break down suspended or accumulated feed on the pond bottom. The research aims to find proteolytic bacterial isolates from pond sediments and the digestive tract of shrimp (<i>Litopenaeus vannamei</i>). <b>Materials and Methods:</b> The materials needed are pond sediment samples, shrimp digestive tract, seawater complete agar (SWCA) medium and skim milk agar medium (SMA). The study used survey methods to determine sampling locations and continued with experimental methods in the laboratory. Nine isolates were obtained from pond sediments and two bacterial isolates were from the shrimp digestive tract. <b>Results:</b> The proteolytic potency test showed that two isolates from pond sediments and one isolate from the digestive tract of shrimp were positive for proteolytic. The largest proteolytic index value reached 6.357. Molecular identification by analyzing the <i>16S rRNA</i> gene sequence shows that PC23 isolate is closely related to the bacterium <i>Exiguobacterium indicum </i>strain KR6 with percent identity 99.44-99.58% and PU32 isolate with <i>Bacillus cereus</i> strain 125 with percent identity 100%. <b>Conclusion:</b> The bacteria obtained can be used as probiotic candidates for the future are <i>Exiguobacterium indicum</i> strain KR6 and <i>Bacillus cereus</i> strain 125.

Biofilm-Forming Heavy Metal Resistance Bacteria From Bungus Ocean Fisheries Port (PPS) West Sumatra as a Waters Bioremediation Agent.

<b>Background and Objective:</b> Heavy metals are one of the most worrisome pollutants due to their toxicity. Prolonged exposure to heavy metals and their accumulation and biomagnification properties adversely affect aquatic biota and human health. The ability of microorganisms to bioremediate heavy metals into non-toxic forms is one solution. The research aims of the study were to find biofilm-forming heavy metal-resistant bacteria isolated from the waters of the Bungus Samudra Fishery Port (PPS), Padang City. <b>Materials and Methods:</b> This study used a marine agar medium modified with the addition of K₂Cr₂O₇, Pb(NO₃)₂ and CdSO₄•H₂O, Marine Broth medium and Congo Red Agar medium. The research methods include, the isolation of bacteria, isolate resistance test to heavy metals, testing the ability of isolates to form biofilms and determine the ability of isolates to reduce heavy metals. Furthermore, molecular identification of bacterial isolates was carried out to determine the type of species. <b>Results:</b> Five heavy metal-resistant bacterial isolates were found that were able to form biofilms, namely isolates B3Cd, B5Cr, B7Pb, B6Pb and B3Pb. The five isolates were able to reduce heavy metal content by 38.67-61.191%. Identification of the best bacterial isolates on each heavy metal tested, namely B3Cd, B5Cr and B7Pb, respectively, showed the type of <i>Acinetobacter schindleri</i>, <i>Acinetobacter</i> sp. and <i>Bacillus</i> sp. <b>Conclusion:</b> These three selected potential isolates can be used as bioremediation agents in metal-polluted waters in the future.

Utilization of Local Microorganisms as Bioactivators to Produce Organic Fertilizers and Analysis of Molecular Bacterial Diversity.

<b>Background and Objective:</b> Local micro organism (LMO) is the result of the fermentation of various mixtures of organic matter. One of the organic materials used, based on the local wisdom of West Sumatra, is tapai (fermented Cassava), which is used as a bio activator in the manufacture of organic fertilizer. The research aims to produce organic fertilizers that meet national quality standards in terms of the physical and chemical quality of fertilizers as well as to determine the diversity of bacteria in bio activators through next-generation sequencing analysis. <b>Materials and Methods:</b> The organic ingredients for bio activators, cow feces as basic fertilizer ingredients, materials for analyzing bacterial diversity, LMO gDNA was extracted using ZymoBIOMICS DNA Miniprep Kit DNA and sequenced using Oxford Nanopore Technology. <b>Results:</b> On a scale of 1-3, the physical quality of organic fertilizers had an average value of 2.58 for smell, 2.83 for texture and 2.58 for color. The chemical quality of organic fertilizers is C-organic (23.56%), nitrogen (1.60%), carbon and nitrogen ratio (14.75%), phosphate (0.47%) and potassium (0.64%). The results of the analysis of bacteria on the bioactivator consisted of 7 phyla, 9 families, 45 genres and 297 species. The most common species is <i>Lentilactobacillus hilgardii</i> (62%). <b>Conclusion:</b> The organic fertilizer produced using the mole tapai bio activator complies with Indonesian national standard 19-7030-2004 based on physical and chemical parameters. The type of bacteria that dominates the bioactivator is the lactic acid bacteria group, which reaches 90%.