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Puji Lestari
Balai Besar Penelitian dan Pengembangan Bioteknologi dan Sumber Daya Genetik Pertanian
Agriculture, Biological Sciences & Forestry Biochemistry, Genetics & Molecular Biology

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KARAKTERISASI DAN STUDI STABILISASI a-AMILASE Bacillus licheniformis TVII.6 MENGGUNAKAN BAHAN ADITIF Puji Lestari; Nur Richana; Rosmimik Rosmimik
BERITA BIOLOGI Vol 10, No 5 (2011)
Publisher : Research Center for Biology-Indonesian Institute of Sciences

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/beritabiologi.v10i5.1914

Abstract

The limited stability of enzyme during long-term storage attributes to its reduced function. In this study, a-amylase from Bacillus licheniformis TVII.6 were formulated with different kind of additives for storage stabilization and better performance. Simultaniously, some minerals and calcium ion were applied to elucidate the inhibition and activation effects to a-amylase. Crude enzyme which was prepared by aceton precipitation was used for this stability test. It demosntrated that 10% of mannitol in citrate phosphate buffer gave the highest residual activity after 3 months of storage (98.5%). Calcium ion influenced the thermal stability of a-amylase and it gave optimum activity at 5 mM CaCl , thus the stability increased from 76.0%/90 C/2 hours to 114.8%/90 C/22 hours in comparison without calcium ions. Calcium ions (5 mM CaCl ) on the stability of a-amylase at 4 C also produced the 2highest residual activity, which remained 100% during 48 hours of incubation. Chemical compounds like FeSO , Na CO and EDTA 4 2 3acted as inhibitors, while (NH ) SO , CuSO , CoSO , MgCl and K HPO did not inhibit activity of a-amylase. NaOH and MnCl 4 2 4 4 4 2 2 4 2 compounds at low concentrations (2 mM) did not inhibit the enzyme but at 10 mM became a-amylase inhibitors. This amylase stability information is very important as a consideration when applying and storing the enzyme, thereby reducing the degradation a-amylase activity.
KARAKTERISASI BAKTERI PENGHASIL ASAM INDOL ASETAT DAN PENGARUHNYA TERHADAP VIGOR BENIH PADI Puji Lestari; Yadi Suryadi; Dwi Ningsih Susilowati; Tri Puji Priyatno; I Made Samudra
BERITA BIOLOGI Vol 14, No 1 (2015)
Publisher : Research Center for Biology-Indonesian Institute of Sciences

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/beritabiologi.v14i1.1859

Abstract

The ability to produce indole acetic acid (IAA) by endophytic bacteria is one of the basic criteria for the use of bacteria as plant growth promoter agent which is essential for the agricultural production.The objectives of this study were to evaluate the ability of 17 bacterial isolates to produce IAA and its effect on improvement of rice seed germination and molecular identification of the selected isolates based on the 16S rRNA gene. The IAA content was determined using Salkowski method measured by spectrophotometer UV-Vis and the effect of endophytic bacteria inoculation on seed germination was done by in vitro assay. Sequences of the selected isolates 16S rRNA amplified by PCR were analyzed the homology against bacterial 16S rRNA database in Genebank. IAA values ranged from 6.632 to 50.053 mg/L with the highest IAA production shown by isolate 6KJ which was followed by 4PB (41.807 mg/L). Bacterial IAA increased rice seed vigor significantly compared to control. However, bacterial inoculation with different concentrations of IAA did not significantly affect the growth of rice plants. Based on the IAA and its effect on seed vigor, 6KJ, 4PB and 2KB were selected for molecular identification. Results showed that the three isolates belonged to Bacillus genus, 6KJ as B. aryabhattai, 4PB belonging to B. cibi and 2KB having 97% homology with B. marisflavi. Further evaluation of the selected endophytic isolates producing IAA is necessary to be carried out to explore their potency as a source of hormone to promote plant growth.
Co-Authors DWI NINGSIH SUSILOWATI I MADE SAMUDRA Nur Richana Rosmimik Rosmimik Tri Puji Priyatno Yadi Suryadi