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Xylanase is an important hydrolytic enzymes with many application in several industries, but to obtain enzyme derived products is not easy. Thus, the optimization of efficient xylanases production is a great interest for biotechnological application. This study aims to determine the type of substrate, medium composition, and optimum conditions of xylanase production by S. costaricanus 45I-3. Determination of substrate type was done by growing the tested bacteria on birchwood xylan, beechwood xylan, oat spelled xylan, corn cobs xylan, and tobacco xylan substrate, meanwhile the determination of medium composition and enzyme production were done by measuring xylanase activity at various substrate concentration and replacing the carbon, nitrogen, phosphate and surfactants source. The results showed that the highest enzymatic index (EI) produced from corn cob xylan substrate at 3.60 meanwhile the second highest was beechwood xylan substrate at 2.87 EI, however this substrate is purer, thus this substrate was selected and used as xylan sources for further optimization measurement. The best xylanase activity (2.29 U/mL) obtained on eighth day after inoculation on rotary incubator at 120 rpm in 28 ºC. Arabinose as the source of carbon generate the highest activity at 3.161 U/mL meanwhile the most preferred source of phosphate is Na2HPO4 (2.37 U/mL). Both source of nitrogen i.e. nitrogen ammonium sulphate (NH4)2SO4 and yeast extract were able to produce xylanase at 2.57 and 2.36 U/mL. The addition of surfactant in production medium showed addition of SDS surfactant (0.146 U/mL) and Tween 80 (0.438 U/mL) showed a negative response by decreasing the activity. The conclusion showed that the xylanase activity was increased after optimization at various C, N, and P sources, and the use of nitrogen source (NH4)2SO4), become a more economical alternative to replacing a nitrogen source yeast extract so it can lower the production costs of xylanase enzyme.

Melioidosis is an emerging zoonotic disease caused by the saprophytic Burkholderia pseudomallei, which infects human and a wide range of animal species. Melioidosis may lead to septicemia and pneumonia in human patients, which can be fatal if the patient is not treated accordingly. The disease is spread in tropical areas and is highly endemic to Southeast Asia and Northern Australia. However, melioidosis is poorly reported in Indonesia, especially in the veterinary field. This research provides serological evidence of antibodies to B. pseudomallei in both captive and wild nonhuman primates. Plasma samples were taken from a total of 390 monkeys in captivities and wild habitats in West Java and Bali, Indonesia. Enzyme-linked immunosorbent assay (ELISA) showed that the seroprevalence was 42.21% for Macaca fascicularis and 43.59% for Macaca nemestrina. Furthermore, the seroprevalence was 53.41% for captive macaques and 17.83% for wild macaques. The findings showed that exposure to B. pseudomallei happened in both captive and wild macaques. Based on this serosurveillance results, further studies such as comprehensive culture and clinical study are required to discover the clinical burden of the disease in nonhuman primates.

Endophytic actinomycetes associated with medicinal plants is very important as source of various bioactive compounds. The fact that more than 99% of microbes that exist in nature may have the potency but still unexplored. Published data regarding diversity of endophytic actinomycetes from T. crispa is mainly based on a culturable approach. This paper describes the first reported data regarding metagenomic analysis on the diversity of endophytic actinomycetes from T.crispa based on 16S rRNA gene using PCR-DGGE. There were some similarities amongst endophytic actinomycetes found in stems, roots, and leaves with soil actinomycetes community in the rhizosphere of T. crispa. There were a total of 21 bands found from the DGGE analysis which were interpreted using Phoretix 1D software. Diversity of actinomycetes in the stems, leaves, roots were represented by 17, 16, and 14 bands, respectively. Whereas only 10 bands represented diversity of actinomycetes in the soil rhizosphere. The 12 dominant and or different bands with 180 bp in size were molecularly sequenced. The A4 and A9 bands have 95% and 86% similarities with Williamsia and Streptomyces, respectively. These similarities were less than 97% thus may indicate novel actinomycetes. The other 10 sequenced bands have closed similarity ranging from 97-100% and they were closely related to the genus Streptomyces, Microbacterium, Amycolatopsis, Actinomadura, Actinoplanes, Actinokineospora, Kibdelosporangium, Williamsia and Kocuria. These findings indicate that diversity of actinomycetes can be found associated with T. crispa.

Composition and abundance of culturable bacteria of four soil samples (Ktr50II, D50II, G50II, and A50II) were analyzed. The soil samples were collected from maize rhizosphere that planted in dryland Lombok Island. Each soil sample give different growth performance of maize in greenhouse experiment. This study was to investigate the relation of maize growth performance with culturable bacterial community of their rhizosphere and the effect of culture media on number of bacterial isolates recovery. The rhizosphere bacteria were cultured and isolated on commercial media (SEA) and non commercial modification media (NAln, NAln-SE and NAln- RE). Thirty four strains rhizosphere bacteria were obtained from four maize rhizophere soil samples. D50II is the soil sample that caused the better growth performance to the maize, contrary to Ktr50II. D50II has significantly highest number of culturable bacterial types, while significantly lowest on Ktr50II. In D50II, at least 17 bacterial isolates contributed to better growth performance in maize and have relative abundance of dominant isolate not more than 35.34%. In comparing the rhizosphere bacteria recovered using different culture media, bacteria cultivated on SEA have different growth characteristic compared with bacteria cultivated on NAln, NAln SE and NAln-RE. Six bacterial isolates showed antagonistic ability when grew on SEA but not in all of three media. Compared with commercial media, non commercial modification media can increase total isolates recovery about 70.6%.

Rhizobacteria have been known for their capability as plant growth promoter through some mechanisms, directly and indirectly. The purpose of this research to screen rhizobacteria of Bacillus spp. and Pseudomonas spp. for their drought tolerance as plant growth promoter of maize (Zea mays). Screening of rhizobacteria as growth promoter of 47 isolates of Bacillus CR and 34 isolates of Pseudomonas CRB resulted 24 and 9 isolates were able to stimulate the growth of maize sprouts, respectively. Further screening of those growth promoter of the rhizobacterial isolates to drought tolerance resulted 7 isolates of Bacillus CR and 6 isolates of Pseudomonas CRB that were able to grow on medium with osmotic pressure -1 and -2 MPa, respectively. Potential rhizobacterial isolates of growth promoter and drought tolerance were tested for antagonist mechanisms which aims to determine ability to live together in one carrier medium if to be made formulation. Both non antagonist rhizobacterial isolates were evaluated for their potential in producing exopolysaccharide (EPS) revealing that CRB 19 and CR 90 exhibited the highest activity of EPS production up to 0.346 mg mL-1 on medium with -2.0 MPa and 0.107 mg mL-1 on medium with -0.73 MPa, respectively. Based on 16S rRNA sequence analysis, it revealed CRB 19 and CR 90 had highest similarities to Pseudomonas aeruginosa strain B2 and Brevibacillus brevis B33, respectively. Those growth promoter and drought tolerant of Bacillus CR and Pseudomonas CRB had potency to be developed as inoculants in dry land agriculture.

Plant-growth promoting rhizobacteria (PGPR) are rhizosphere associated soil-borne bacteria that can enhance plant growth and inhibit the development of root pathogens. Many soil bacteria have been used as PGPR, and one of them is Bacillus sp. The implementation of PGPR is constrained by genotype fluctuation that makes it inactive on the rhizosphere. Our previous study had characterized and revealed that 11 Bacillus sp. isolated from the soybean plant rhizosphere were PGPR. To asses and compare the genetic diversity of these isolates, Amplified Ribosomal DNA Restriction Analysis (ARDRA) and DNA sequence analysis of 16S rRNA were conducted. The construction of Neighbor-joining trees and bootstrap analysis of 100 resamples of ARDRA and 16S rRNA gene sequences were performed using Treecon software for windows ver. 1.3b. ARDRA analysis was done by using four restriction enzymes (RsaI, HaeIII, CfrI and HinfI), resulting in four phylotypes, respectively phylotype I (Bacillus sp. Cr24, Cr33, Cr64 and Cr68), phylotype II (Bacillus sp. Cr 31 and Cr66), phylotype III (Bacillus sp. Cr44 and Cr71) and phylotype IV (Bacillus sp. Cr67, Cr28 and Cr69). Results of BLASTN from 16S rRNA gene sequences showed that these isolates are genetically diversed. The evolution relationship of Bacillus sp. could be shown by the 16S rRNA gene sequences analysis, while ARDRA based on the digestion sites showed their variability.

The 1-aminocyclopropane-1-carboxylate (ACC) deaminase (EC4.1.99.4) is an enzyme produced by some soil bacteria to degrade ACC (the immediate precursor of ethylene) to reduce ethylene biosynthesis in higher plants. Increased concentrations of ethylene in plant tissues, which are triggered by various biotic and abiotic stresses, inhibits plant growth and weakens the plant defense against the stressors. Various findings on the successful use of ACC deaminase producing bacteria for plant growth under unfavorable soil conditions are inspiring their use in tropical peat-soil-agriculture, which possesses bio-physical constraints. It has been proven that inoculation of plants with ACC deaminase producing bacteria decreased ethylene inhibition generated by unfavorable environmental conditions, such as nutrient shortage, flooding, drought, high salts, and the presence of heavy metals and organic pollutants. Understanding the mechanisms by which ACC deaminase-producing bacteria act to reduce plant stress and the fitness of bacterial traits with the properties and constraints of peat-soils becomes a key to utilize these bacteria in improving crop productivity. The bacteria may ameliorate plant stress as well as promote plant growth under seasonal bio-physical changes of peat-soils that are usually encountered in the field.

Acid-aluminium sensitive mutants of symbiotic bacterium Bradyrhizobium japonicum BJ11 (designated as AAS11) and KDR15 (designated as AAS15) were constructed by mini-Tn5 transposon mutagenesis to study genes involved in acid-aluminium tolerance (AAT) in B. japonicum. Transposon delivery was carried out through conjugation between B. japonicum strains as recipients and Escherichia coli S17-1 (ë pir) carrying pUTmini- Tn5Km1 as a donor strain. The result showed that frequency of transconjugation was in the range of 6.7 x 10-7 to 7.1 x 10-6 cell per recipients. AAS11 and AAS15 mutants did not grow on Ayanaba media (pH 4.5) containing 50 μM Aluminium. These mutants remained able to form root nodules of Siratro (Macroptilium arthropurpureum) plants revealing genes interrupted by transposon which were responsible for acid-Al tolerance did not correlate with the nodulation genes. Strains tolerant to acid-aluminium and their mutants with a wild type sensitive to acidaluminium were characterized by accumulating phosphate and aluminium absorption. Compared to the wild type acid-aluminium tolerant B. japonicum, there was approximately a three- to eight-times decrease in phosphate accumulation and a five- to seven-times increase in aluminium absorption by these mutants. These results suggest that aluminium and phosphate contents in the bacterial cells may be involved in mechanisms of acid-Al tolerance of B. japonicum grown in acid-aluminium stress conditions.

Xanthomonas axonopodis pv. glycines (Xag) is the causal agent of bacterial pustule disease of soybeans. A nonpathogenic mutant of Xag (M715) was constructed employing transposon mutagenesis which showed similar epiphytic survival in planta to its wild type strain (YR32). The objective of this work was to identify and to analyze genes involved in pathogenicity in Xag YR32. Inverse Polymerase Chain Reaction (IPCR) was used to isolate the DNA flanking transposon insertion. A 1.3 kb flanking DNA fragment was sequenced and analyzed employing BLAST program to study homology, the position of transposon insertion and to predict the structure and function of the gene. One of the Open Reading Frames (ORFs) shared homology with inner membrane proteins (imps) of Xanthomonas axonopodis pv. citri (GenBank accession No. NC 003919). Northern blot analysis revealed that an imps gene was monocistronic and the size of imps mRNA in YR32 was slightly longer than in M715. Reverse Transcriptase- PCR analysis demonstrated that the imps transcript in M715 was much less abundant than in the wild type YR32. Transposon (mini-Tn5-Kmr-Tpr) was determined to be inserted close to the end of C-terminal region of imps gene and might be sufficient to destabilize the imps transcript in M715 and so influence effectors transportation from Xag to plant cell.

Antifungi-producing rhizobacteria have been recognized playing an important role in plant disease suppression. In our laboratory, 13 indigenous soybeans' rhizobacteria Pseudomonas sp. that showed strong growth inhibition of root pathogenic fungi, Rhizoctonia solani, Fusarium oxysporum and Sclerotium rolfsii, have been isolated from rhizosphere of soybean plant. For further understanding, the genetic diversity of the antifungi-producing Pseudomonas sp. was investigated using Amplified 16S rDNA Restriction Analysis (ARDRA) and 16S rRNA gene sequences analysis. 16S rDNA were amplified by PCR technique and digested with restriction endonuclease HaeIII, RsaI and AluI. Sequences of 16S rRNA gene were analyzed using the BLAST program for similarity searches on sequence databases. ARDRA based dendrogram analysis was carried out by neighbor-joining of TREECON 1.3b software package. ARDRA indicated the variability of Pseudomonas sp. based on the digestion sites. Dendrogram clustering analysis based on the restriction enzymes profile of the amplified rDNA distinguished Pseudomonas sp. into 7 ribotype groups. The sequences of 16S rRNA gene confirmed that the isolates belonging to Pseudomonas sp. and the phylogenetic tree formed 4 clusters. There was a quite overlap among ARDRA groups and 16S rRNA sequence clusters. This finding suggested that antifungal producing Pseudomonas sp. were present in the rhizosphere of soybean plant and the level of genetic diversity exist within these species. Sequence analysis of the 16S rRNA gene of the Pseudomonas sp. with an identical ARDRA pattern confirmed that members of an ARDRA group were closely related to each other.

Tempe is traditional Indonesian food. It has a variety of tastes, sometimes with a hint of bitterness, which may differ in intensity. The cause of bitterness in tempe has never been reported previously. In this study, the aim is to identify whether bacteria play a role in the formation of bitter tastes in tempe. Sensory tests were carried out in order to determine the scores of bitter-taste-intensity in tempe. The sensory test on EMP, WJB, CLR, DRG, and MLB tempe shows that EMP tempe has the highest score (2.3) and WJB has the lowest (1.3). It is revealed that the processing method has no impact on the formation of the bitter taste in tempe. Plating analysis, showed that EMP soaking water contained a higher number of Enterobacteria group bacteria, approximately 103-104 CFU ml-1 and spore-forming bacteria groups, 102 CFU ml-1, compared to WJB. Similarly, other bacteria groups in fresh EMP tempe was 102 CFU g-1 higher than those in fresh WJB tempe. Based on sequencing the16S rRNA gene, the dominant bacteria on PCA media in EMP tempe are Acetobacter indonesiensis, Klebsiella pneumoniae, Bacillus subtilis, and Flavobacterium sp. On the other hand those in WJB tempe were Klebsiella sp., Brevundimonas sp., Bacillus sp., Pseudomonas putida, and Acinetobacter sp. Bacillus, a group of proteolytic bacteria was found 105 CFU m-1 higher in the soaking water of EMP compared to WJB. Nevertheless, the types and numbers of fungi were not significantly different between tempe types. Accordingly, it is concluded that the difference in the number and the types of bacteria involved in the tempe production process leads to the difference in the bitter taste intensity in both EMP and WJB tempe.

A rapid and simple method to amplify genomic DNA sequences flanking mini-Tn5 transposon insertion was developed. This technique can be used to determine the location and orientation of the transposon insertion within genomic DNA of the bacteria. Based on the mini-Tn5Km1 transposon sequence, PCR primers can be designed to specifically amplify the DNA sequences flanking mini-Tn5 transposon by inverse polymerase chain reaction (inverse PCR) directly, upstream and downstream of the transposon insertion. The method involves: (i) digestion with a restriction enzyme that does not cut mini-Tn5Km1 sequence; (ii) self-ligation under conditions favoring the production of monomeric circles; and (iii) inverse PCR reaction using primers designed from mini-Tn5Km1 sequence to amplify the DNA sequences flanking mini-Tn5Km1 transposon insertion. Feasibility and reliability of this method were demonstrated with mini-Tn5Km1 mutants of the microaerobic magnetic bacterium Magnetospirillum magneticum AMB-1 which are defective in magnetosomes synthesis. The inverse PCR products amplified from these mutant genomes showed the correct fragments as determined through Southern hybridization and DNA sequence analysis.