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Exploration and characterization of exopolysaccharide-producing bacteria from soil in West Kalimantan for improving sandy soil aggregation Harahap, Nasrul; Santosa, Dwi Andreas; Gofar, Nuni
Journal of Degraded and Mining Lands Management Vol 5, No 4 (2018)
Publisher : University of Brawjiaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (111.355 KB) | DOI: 10.15243/jdmlm.2018.054.1373

Abstract

Exopolysaccharide (EPS) is a complex mix of macro-molecular electrolyte contained in the outer cells of bacteria excreted as mucus and has a role in soil aggregation. This study aims to obtain bacteria that have a high potential for exopolysaccharide-producing bacteria. A total of 112 isolates of exopolysaccharide-producing bacteria were isolated from rubber soil rhizosphere, secondary forest, and shrubs in PT. Hutan Ketapang Industri is the result of isolation on ATCC no.14 medium. Based on the observations of a morphological colony of these isolates, most of them similarities of color and shape but only 25 colonies are different isolates were obtained based on colony morphology. However, only 10 isolates formed a thick mucus or slimy when cultured on MacConcey agar. the results show that obtained three isolates of exopolysaccharide-producing bacteria have a higher value of the dry weight i.e. isolates RB292 (7.53 mg/mL) followed by RB51 (7.55 mg/mL), and RB241 (1.75 mg/mL) with 2% sucrose. Isolates RB51 and RB292 increasing significantly soil aggregate stability at 2% dosage of organic matter with soil aggregate stability index from 30.61% to 47.87% and 45.79%. Homology of the isolates with known bacteria i.e. isolate RB51 was 98.86% homolog with Klebsiella sp. LW-13, isolate RB241 was 98.65% homolog with Klebsiella pneumonia strain DSM 30104 and isolate RB292 was 98.83% homolog with Burkholderia anthina strain MYSP113
The potential of exopolysaccharide-producing bacteria from rhizosphere of rubber plants for improving soil aggregate Harahap, Nasrul; Santosa, Dwi Andreas; Gofar, Nuni
Journal of Degraded and Mining Lands Management Vol 5, No 3 (2018)
Publisher : University of Brawjiaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (539.583 KB) | DOI: 10.15243/jdmlm.2018.053.1275

Abstract

 This study aimed to examine the effect of bacteria found in the rhizosphere of rubber plants in producing exopolysaccharides to improve aggregate stability of sandy soils. Samples of soil have been taken in rhizosphere of rubber plants in West Kalimantan. Serial soil samples were diluted and cultured on ATCC no.14 medium to select potential bacteria to produce exopolysaccharides. Forty-five isolates of exopolysaccharide-producing bacteria isolated from the rhizosphere of rubber plants was inoculated on ATCC no.14 medium. Based on the observations of morphological colony of these isolates, most of them had similarities in colour and shape so that only ten different isolates were obtained based on the morphological colony. Ten isolates were re-grown on MacConcey medium. Three isolates formed thick or slimy mucus when cultured on MacConcey medium. Three isolates grown on the medium of ATCC 14 resulted in dry weight of exopolysaccharide (mg/mL) varying from 0.28 to 7.59 mg/mL with sucrose and glucose as carbon sources. The results of the molecular identification of the three isolates of Klebsiella sp. LW-13, Klebsiella pneumoniae strain DSM 30104 and Burkholderia anthina strain MYSP113 showed that Klebsiella sp. LW-13 and Burkholderia anthina strain MYSP113 with 2% organic matter increased soil aggregate stability from highly unstable (30.67%) to unstable (45.01-48.20%). This aligned with the results by scanning electron microscopy (SEM) on treated soil and without bacteria treatments.