Ari Susilowati

Screening and identification of lignolytic bacteria from the forest at eastern slope of Lawu Mountain

Lignin is the most abundant organic material on earth after cellulose and hemicellulose. The lignolytic bacteria were capable of degrading substantial aromatic compounds of high redox potential both phenol and non-phenol which make up about 90 % of the lignin polymer. Most of the litter on the forest floor of the eastern slope of Lawu Mountain was pine-leaves Pinus merkusii biomass. The purposes of this study were to obtain bacteria that have lignolytic activity, identify the bacteria and determine their genetic relationship. The soil samples were taken from under the litter that had begun to decay on the forest floor. Lignolytic activity test was done by measurement of degradation index using methylene blue (MB) on Luria Bertani agar and degradation percentage test using UV-Vis spectrophotometer at λ 664 nm in three times repeat measurements. Identification of lignolytic bacteria based on 16S rRNA encoding gene sequence similarity using BLAST at NCBI. Phylogenetic relationship analysis was done using MEGA 7.0 software. The results showed that from three locations there were six isolates of high-activity lignolytic bacteria. The highest activity was found in isolate B12 by 17 % degradation. Isolate A12 was identified as Staphylococcus saprophyticus that has the similarity of 99 %. Isolates B12, B14 and C09 were identified as for genus Pseudomonas with similarity of 98 %. Isolate B12, B14, B16, C08 were in a subgroup with C09 and Pseudomonas aeruginosa USS25W AY905552.1. Isolate A12 was in a subgroup with Bacillus sp. DSM8724 Y76448.1.Lignin is the most abundant organic material on earth after cellulose and hemicellulose. The lignolytic bacteria were capable of degrading substantial aromatic compounds of high redox potential both phenol and non-phenol which make up about 90 % of the lignin polymer. Most of the litter on the forest floor of the eastern slope of Lawu Mountain was pine-leaves Pinus merkusii biomass. The purposes of this study were to obtain bacteria that have lignolytic activity, identify the bacteria and determine their genetic relationship. The soil samples were taken from under the litter that had begun to decay on the forest floor. Lignolytic activity test was done by measurement of degradation index using methylene blue (MB) on Luria Bertani agar and degradation percentage test using UV-Vis spectrophotometer at λ 664 nm in three times repeat measurements. Identification of lignolytic bacteria based on 16S rRNA encoding gene sequence similarity using BLAST at NCBI. Phylogenetic relationship analysis was done using MEG...

In vitro testing of antibacterial activity of extracts of seed cardamom (Amomum compactum) against by Aeromonas hydrophila

Putri SDK, Susilowati A, Setyaningsih R. 2016. In vitro testing of antibacterial activity of extracts of seed cardamom (Amomum compactum) against by Aeromonas hydrophila. Biofarmasi 14: 10-18. One of the obstacles that hinder the cultivation of common freshwater fish is the presence of pathogenic bacteria Aeromonas hydrophila. These bacteria cause Motile Aeromonas Septicemia (MAS). One effort against MAS on freshwater fish is the use of cardamom seed (Amomum compactum). The purpose of this study was to know the antibacterial activity and get the minimum concentration of cardamom seed extract that was able to inhibit A. hydrophila in vitro. Cardamom seed extraction was done by stratified maceration using three solvent, i.e., n-hexane, ethyl acetate, and methanol. Antibacterial activity was conducted using disc diffusion method with 100% concentration for each extract, solvents, only bacteria culture without the extract as negative control and positive control for chloramphenicol 3,4%. Minimum Concentration Inhibitory test (MIC) performed using extracts of the most widespread inhibitory zone. The extract concentrations tested 5,71%, 2,70%, 1,35%, 0,68%, 0,34%, 0,17%(b/v),and 0% as a negative control, while the antibiotic chloramphenicol as a positive control. Data analyzed using Analysis of Variance test (ANOVA) and Duncans Multiple Range test (DMRT) level of 5%. Cardamom seed extracted with n-hexane, ethyl acetate and methanol as a solvent were 11,1 g, 10 g, and 15,1 g extract respectively. Inhibition zone of 100% cardamom seed extract with the solvent n-hexane, ethyl acetate, and methanol were 5,25 mm, 6,25 mm and 5,75 mm respectively. MIC values in the ethyl acetate extract of A. hydrophila were 2,70%.

Endophytic bacteria producing antibacterial against methicillin-resistant Staphylococcus aureus (MRSA) in seagrass from Rote Ndao, East Nusa Tenggara, Indonesia

Fitri DS, Pangastuti A, Susilowati A, Sutarno. 2017. Endophytic bacteria producing antibacterial against methicillin-resistant Staphylococcus aureus (MRSA) in seagrass from Rote Ndao, East Nusa Tenggara, Indonesia. Biodiversitas 18: 733-740. Methicillinresistant Staphylococcus aureus (MRSA) are bacteria that resistant to the various type of antibiotics and yet cannot be handled comprehensively. The discovery of new antibiotic from endophytic bacteria in seagrass of Rote Island is an option to overcome the resistance. The aims of this research were to screen endophytic bacteria inhibit MRSA from seagrass, to determine the species of the endophytic bacteria and the genetic relationship. Isolation of endophytic bacteria has carried out by inoculating surface sterilization seagrass leaves on Marine Agar (MA) medium. Selection of potential endophytic bacteria-producing anti-MRSA has done using overlay method against MRSA, gram-positive Bacillus subtilis, and gram-negative Escherichia coli. Identification of the endophytic bacteria based on the sequence of 16S rRNA encoding gene. The results showed that there were eight isolates of endophytic bacteria which have antibacterial activity against MRSA of seagrass Enhalus acoroides, Thalassia hemprichii, and Cymodocea rotundata in the Litianak and Oeseli Beaches, Rote Ndao. The diameter of inhibition zone was between 0.65-18.27 mm with narrow spectrum with broad spectrum antibacterial activity. The eight potential endophytic bacteria identity were Bacillaceae E2M1, Bacillaceae E2M3, Bacillus E2M4, Bacillus E2M7, Bacillaceae E2M8, Pseudomonadaceae C1M7, Shewanellaceae C2M3, and Rhodobacteraceae T1M3. Most of the isolates can be said to be a new species as the percent similarity of 16S rRNA gene sequence was less than 95% and promising to produce new antibacterial compounds. Phylogenetic relationship showed some isolates clustering in different groups that present the diverse groups of endophytic bacteria were found.