Four bacterial isolates from Ranu Pani and Ranu Grati in east java had been revealed to be potentials to produce IAA (PIS isolate), phosphate solubilizer (GPS isolate), cellulose hydrolysis (PSS isolate) and, amylum hydrolysis (PAS), two dominant bacterial isolates from Rani Pani (PØD isolate) and Ranu Grati (GØD isolate) which were co-cultured with microalgae promoted microalgae growth, yet its taxonomical position has not been clearly known. The aim of this study was to identify those bacterial isolates using 16S rRNA barcode. This research conducted by gDNA isolation, the 16S rRNA sequence was amplified using 27F and 1492R primers. Reconstructed phylogenetic trees and genetic distance analysis showed that the isolate PIS and PSS identified as Bacillus cereus Group closely related to Bacillus paramycoides. PAS isolate identified as Bacillus subtilis Group closely related to Bacillus amyloliquefaciens, GPS isolate identified as novel species in genus Enterobacter, and two dominant isolates (PØD and GØD) identified as Enterobacter cloacae complex closely related to Enterobacter cloacae. The genomic approach and additional phenotypes-examination are required to clarify its taxonomical position.

No abstract

The consortium of various types of bacteria from lakes in East Java has the potency to stimulate microalgae Chlorella vulgaris growth. Increased microalgae density from co-culture has an excellent potency for sources of biomass that can be developed for renewable energy. Several stages conducted of this research started from an exploration of IAA producing bacteria and amylolytic bacteria from several East Java Lakes; then, the highest bacterial isolates were identified with morphological and genotypical characteristics. The well-characterized bacterial isolates were used for the microbial consortium in co-culture with C. vulgaris. The treatment used in this study as follows: I) C. vulgaris without bacteria culture as a control, II) amylolytic bacteria + C. vulgaris, III) IAA-producing bacteria + C. vulgaris, IV) potential amylolytic bacteria and IAA-producing bacteria + C. vulgaris. The exploration result of potential bacteria from Ranu Pani, Ranu Regulo, Telaga Ngebel, and Ranu Grati lakes was found 53 amylolytic bacterial isolates, and 90 isolates IAA-producing bacteria. The highest amylolytic bacteria (isolate L) is related to Bacillus amyloliquefaciens, while the most elevated IAA-producing bacteria (isolate C) is related to Bacillus paramycoides. The highest cell density was produced in treatment III, reaching 2.7 x 106 cells/mL on day 50th. The treatments with supplement bacteria showed a significant effect for accelerating the growth of microalgae compared to control.

No abstract

Abstract. Nisa IK, Prabaningtyas S, Lukiati B, Saptawati RT, Rodiansyah A. 2021. The potential of amylase enzyme activity against bacteria isolated from several lakes in East Java, Indonesia. Biodiversitas 21: 42-49. Indonesia is one country that has water resources having an abundance of microbial diversity, but not explored massively. This study aims to measure the amylase activity quantitatively from 53 amylolytic bacterial isolates from Ranu Pani, Ranu Regulo, Ranu Grati, and Ngebel Lake; also it identifies the isolate with the highest amylase enzyme activity. The amylase enzyme activity test calculates with DNS (Dinitrosalycylic acid) method, molecular identification of the highest bacterial isolate is based on the 16S rRNA gene. Its relationship is determined through the phylogenetic tree with the Neighbor-Joining (NJ) method. The results showed that the fifty-three bacterial isolates have amylase activity about 0.000-0.016 units/mL. The KN bacterial isolate from Ranu Ngebel was the highest amylase activity, producing enzyme around 0.016 units/mL, while isolate G20 from Ranu Grati was the lowest, reaching about 0.0001 Unit/mL. Based on the morphological and molecular identification, the KN bacterial isolate is classified as the Bacillus cereus group with 99.4-100% sequence similarity, closely related to Bacillus paramycoides (NR 157734.1).