Antibacterial Compounds from Microorganisms Isolated from Deep Sea Sediment: A Mini Review

The search for new antibacterial compounds using sources derived from marine biota is interesting to develop, considering that Indonesia has diversity of a very large microorganisms and has the potential to produce antibacterial substances. One of the microbial resources that has not been widely exploited is the microorganisms present in deep sea sediments. The deep sea has variations in the availability of nutrients, light, oxygen, concentration, pressure, salinity, and temperature. This condition also triggers marine microorganisms to develop unique physiological abilities. The physiological ability of deep sea microorganisms not only to survive, but also has an impact on their ability to produce unique metabolites that are not owned by terrestrial microorganisms. Here we will review some reported study on the search of antibacterial compounds from microorganisms isolated from the deep sea sediment. The fundamental basic of antibacterial will be discussed followed by several reported antibacterial compounds from the sediment bacteria. This opens door for the search of new microorganisms that produced new chemical compounds with beneficial application in human health as well as in other field.

AHL-Lactonase Producing Psychrobacter sp. From Palk Bay Sediment Mitigates Quorum Sensing-Mediated Virulence Production in Gram Negative Bacterial Pathogens

Quorum sensing (QS) is a signaling mechanism governed by bacteria used to converse at inter- and intra-species levels through small self-produced chemicals called N-acylhomoserine lactones (AHLs). Through QS, bacteria regulate and organize the virulence factors’ production, including biofilm formation. AHLs can be degraded by an action called quorum quenching (QQ) and hence QQ strategy can effectively be employed to combat biofilm-associated bacterial pathogenesis. The present study aimed to identify novel bacterial species with QQ potential. Screening of Palk Bay marine sediment bacteria for QQ activity ended up with the identification of marine bacterial isolate 28 (MSB-28), which exhibited a profound QQ activity against QS biomarker strain Chromobacterium violaceum ATCC 12472. The isolate MSB-28 was identified as Psychrobacter sp. through 16S-rRNA sequencing. Psychrobacter sp. also demonstrated a pronounced activity in controlling the biofilm formation in different bacteria and biofilm-associated virulence factors’ production in P. aeruginosa PAO1. Solvent extraction, heat inactivation, and proteinase K treatment assays clearly evidence the enzymatic nature of the bioactive lead. Furthermore, AHL’s lactone ring cleavage was confirmed with experiments including ring closure assay and chromatographic analysis, and thus the AHL-lactonase enzyme production in Psychrobacter sp. To conclude, this is the first report stating the AHL-lactonase mediated QQ activity from marine sediment bacteria Psychrobacter sp. Future work deals with the characterization, purification, and mass cultivation of the purified protein and should pave the way to assessing the feasibility of the identified protein in controlling QS and biofilm-mediated multidrug resistant bacterial infections in mono or multi-species conditions.

TEST THE ABILITY OF SEDIMENT BACTERIA ISOLATES IN DEGRADATING PHENOL

Phenol degrading bacteria can be found in various habitats in marine environments. This study aims to obtain bacteria from sediments that are able to degrade phenol. The process of bacterial purification and degradation was carried out from August to September 2018 at the Marine Microbiology Laboratory, Department of Marine Sciences, Faculty of Fisheries and Marine, University of Riau. Analysis of the reduction in phenol concentration was carried out using the APHA 5530 method using UV-VIS spectrophotometry conducted at the Health and Environment Laboratory. The bacterial isolates used as test bacteria were isolates BF1A, BF4B and BF9C. Bacterial and biochemical tests were carried out for all bacterial isolates. Two isolated showed mehyl red negative, all isolates were motile. Three isolates were positive catalase, able to ferment glucose and sucrose fermented citrate and two isolat were Gram negative bacterial. The three bacterial isolates were able to degrade phenol with the highest degradation for 1ppm shown in isolates BF1A, the highest degradation of concentrations of 2 ppm and 3 ppm was shown in isolates BF9C. Thus, the isolat BF9C was able to degrade the highest phenol.

Isolation and Diversity of Sediment Bacteria in the Hypersaline Aiding Lake, China

A total of 343 bacteria from sediment samples of Aiding Lake, China, were isolated using nine different media with 5% or 15% (w/v) NaCl. The number of species and genera of bacteria recovered from the different media significantly varied, indicating the need to optimize the isolation conditions. The results showed an unexpected level of bacterial diversity, with four phyla (Firmicutes, Actinobacteria, Proteobacteria, and Rhodothermaeota), fourteen orders (Actinopolysporales, Alteromonadales, Bacillales, Balneolales, Chromatiales, Glycomycetales, Jiangellales, Micrococcales, Micromonosporales, Oceanospirillales, Pseudonocardiales, Rhizobiales, Streptomycetales, and Streptosporangiales), including 17 families, 41 genera, and 71 species. In this study, the predominant phyla included Firmicutes and Actinobacteria and the predominant genus included Halomonas, Gracilibacillus, Streptomyces, and Actinopolyspora. To our knowledge, this is the first time that members of phylum Rhodothermaeota were identified in sediment samples from a salt lake. This study has identified at least four novel isolates.

PENAPISAN AKTIVITAS AMILOLITIK DAN ANTIBAKTERI DARI BAKTERI SEDIMEN PERAIRAN PULAU LEMUKUTAN

Resistansi bakteri saat ini menjadi permasalahan dalam bidang kesehatan. Hal ini dikarena meningkatnya Multiple Drug Resistance (MDR) oleh bakteri patogen. Oleh karena itu, perlu dilakukan penelitian mengenai sumber senyawa antibakteri, salah satunya dari bakteri pada sedimen laut. Tujuan dari penelitian ini adalah untuk mengetahui aktivitas antibakteri pada bakteri sedimen laut dari Perairan Pulau Lemukutan. Isolasi bakteri dari bakteri sedimen laut diperoleh sebanyak 4 isolat. Penapisan aktivitas antibakteri dilakukan dengan metode cross streak. Bakteri patogen yang digunakan adalah Eschericia coli, Staphylococcus aureus, Vibrio cholerae, Pseudomonas aeruginosa, dan Salmonela typhimurium. Aktivitas antibakteri terbaik diperoleh pada bakteri SKA04 dapat menghambat bakteri patogen S. typhimurium. Penapisan aktivitas enzim ekstraseluler dilakukan untuk mengetahui potensi isolat bakteri sedimen laut dalam menghasilkan enzim amilolitik dan lipase. Uji aktivitas ezim amilolitik diperoleh 3 isolat menghasilkan enzim amilolitik yaitu SKA02, SKA03 dan SKA04 yang ditandai dengan terbentuknya zona bening di sekitar koloni bakteri.AMYLOLYTIC AND ANTIBACTERIAL ACTIVITIES ASSESSMENT OF SEDIMENTARY BACTERIA OF LEMUKUTAN ISLAND. Bacterial resistance is currently a complication in the health sector. This is due to receiving several resistance drugs (MDR) by pathogenic bacteria. Therefore, it is necessary to do research on antibacterial sources, one of which is from bacteria in marine sediments. The purpose of this study was to study the antibacterial activity of marine sedimentary bacteria from Lemukutan Island. The isolation of bacteria from marine sediment bacteria obtained 4 isolates. Screening of antibacterial activity was carried out using the cross streak method. The pathogenic bacteria used are Escherichia coli, Staphylococcus aureus, Vibrio cholerae, Pseudomonas aeruginosa, and Salmonela typhimurium. The best antibacterial activity obtained in SKA04 bacteria can inhibit pathogenic bacteria S. typhimurium. Screening of extracellular enzyme activity was carried out to determine the potential of marine sediment bacteria isolates in producing amylolytic enzymes and lipases. The amylolytic enzyme activity test obtained 3 isolates which produced amylolytic enzymes, namely SKA02, SKA03 and SKA04 which were characterized by the formation of clear zones around bacterial colonies.