<p><em>The aim of the study was to isolate lactic acid bacteria (LAB) from palm oil sap and to investigate the anti microbial activity of LAB against pathogen bacteria, Staphylococcus aureus and Escherichia coli using disc diffusion method. Palm oil sap were enriched using spesific medium MRS (Man Rogosa Sharpe) broth overnight, serial dilution were conducted and the culture were spread on the surface of MRS agar and then incubated for 48 hours. The result showed the total colonies of LAB were 1,4 x 107 CFU/mL. 6 colonies were randomly selected namely EHN1, EHN2, EHN3, EHN4, EHN5 and EHN6. The selected colonies are classified as Gram positive and bacilli in morphology. Antimicrobial activity against pathogenic bacteria was investigated using disc diffusion method. Antimicrobial activity of isolates against E.coli and S.aureus were 12,2 mm; 9mm; 11mm; 11mm; 10,5mm; 12 mm dan 13,5mm; 11mm; 12mm; 11,5mm; 12mm; 12,5mm respectively. from these result it can be concluded that LAB isolated from oil palm sap has potential as probiotic.</em></p>

Abstract. Fachrial E, Putri RRJS, Lister INE, Anggraini S, Harmileni, Nugroho TT, Saryono. 2020. Molecular identification of cellulase and protease producing Bacillus tequilensis UTMSA14 isolated from the geothermal hot spring in Lau Sidebuk Debuk, North Sumatra, Indonesia. Biodiversitas 21: 4719-4725. The industrial need for stable microbial enzymes tends to increase every year. The aim of this study was to isolate and identify the protease and cellulase producing thermophilic bacteria isolated from the geothermal spring of Lau Sidebuk Debuk, North Sumatra, Indonesia. The protease activity was determined based on the formation of halo zone on Skim Milk Agar, while cellulase was confirmed using CMC plate agar method. Nine bacterial isolates were successfully obtained from the sediments and water, and both activities were observed in only one isolate, known as UTMSA14. These isolates were characterized biochemically and morphologically. The molecular identification of UTMSA14 was done by 16S rRNA sequencing based on BLAST and phylogenetic analysis using MEGA X. Phylogenetic analysis showed that UTMSA14 clustered together with Bacillus tequilensis strain 10b (accession number NR_104919.1), which ascertained the isolate as Bacillus tequilensis strain 10b (accession number NR_104919.1). This is the first report of a thermophilic bacteria isolated from Lau Sidebuk Debuk hot springs, with the ability to produce cellulase and protease. further research is needed to purify and characterize the resulting enzymes, with a potential for industrial applications.

Abstract. Fachrial E, Krisdianilo V, Harmileni, Lister INE, Nugroho TT, Saryono. 2021. Isolation, characterization, activity test and molecular identification of thermophilic bacteria producing proteases from Dolok Tinggi Raja Natural Hot Springs, North Sumatra, Indonesia. Biodiversitas 22: 1725-1732. Proteases are complex enzymes that can be applied in both commercial products and physiological fields. This enzyme accelerates the breakdown of peptide bonds in polypeptides and proteins using hydrolysis reactions, transforming them into simpler bonds. In recent years, the demand for protease enzymes in Indonesia is still dependent on imported products, and there has also been an increase in their use. This is because there are many advantages in terms of efficiency, environmental friendliness, and its ability to catalyze a reaction without by-products. Proteases dominate the enzyme market with a total of 70% sales. Furthermore, they are manufactured from thermophilic bacteria as a solution to the problem of enzyme use in industries, where enzymes are easily damaged at high temperatures. The thermophilic protease enzyme can be found in thermophilic microorganisms living in extreme temperatures such as hot springs. There are lots of mountainous areas in North Sumatra Province, Indonesia with many hot springs. For example, the Dolok Tinggi Raja Natural Hot Springs of Simalungun District which has a water temperature of 50oC with a pH of about 6, the potential of which still needs to be explored. This study aims to isolate and determine the activity and molecular structure of thermophilic bacteria producing protease in Dolok Tinggi Raja Natural Hot Springs. Protease activity was determined based on the formation of clear zones in Skim Milk Agar medium. In addition, a total of 20 isolates were successfully obtained from sediment and water. Each was tested biochemically and morphologically, where 19 isolates had the activity of proteases, with the highest in isolate UTMTR VK S9 of 23.67 U/mL. Molecular identification was performed by the amplification of 16SrRNA gene based on BLAST and phylogenic analysis with MEGA X. Phylogenic results showed that isolate UTMTR VK S9 possessed similarities to Bacillus paralicheniformis strain A30103. Meanwhile, more research is required to purify enzymes for application in the industrial world.

Lactic acid bacteria (LAB) could be isolated from various fermented food products. One potential source of LAB is traditional fermented food. The aim of the study was to isolate and investigate antimicrobial activity of LAB isolated from traditional Batak food, “naniura”. The LAB isolates were characterized by Gram staining, fermentation type and catalase test. The investigation of antimicrobial activity of LAB against pathogenic bacteria were conducted using disc diffusion method. The results showed that 6 isolates of BAL were successfully isolated namely BN1, BN2, BN3, BN4, BN5 and BN6 had characteristics of Gram positive, rod shaped and catalase negative. All selected isolate have heterofermentation type. Four isolates (BN1, BN2, BN5 and BN6) were able to inhibit S. aureus, E. coli and S. typhi with inhibition zone diameters ranging from 6,9 to 12,3 cm. Based on the result, it was concluded that LAB isolated from naniura has potential as a source of probiotics.

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