The Ability of Soil Bacteria from Liwa Botanical Gardens to Produce Indole Acetic Acid Hormone (AIA)

Hormon AIA berperan besar dalam memperbesar dan memperpanjang sel, pembelahan sel, khususnya pada daerah ujung tanaman. Bakteri yang memiliki kemampuan dalam menghasilkan hormon AIA diantaranya  Enterobacter sp., Azospirillum sp., Klebsiella sp., Alcaligenes faecalis, Azoarcus sp., Serratia sp., Azotobacter sp., Cyanobacteria, Erwinia herbicola, Pseudomonas sp., Rhizobium, Bradyrhizobium, Agrobacterium tumafaciens. Sintesis AIA ini memerlukan senyawa tambahan berupa triptopan. Namun beberapa bakteri mampu memproduksi AIA tanpa penambahan prekursor. Penelitian ini bertujuan untuk memperoleh isolat bakteri penghasil hormon AIA dari tanah Kebun Raya Liwa. Pada ini diawali dengan isolasi bakteri tanah asal Kebun Raya Liwa, selanjutnya dilakukan uji kemampuan produksi AIA secara kuantitatif tanpa penambahan triptopan. Pengujian produksi AIA secara kualitatif dilakukan dengan menggunakan media Nutrien Broth dengan metode spektrofotometri dengan penambahan reagen salkowsky dan dilakukan pengamatan setelah 72 jam inkubasi. Data yang didapatkan disajikan dalam bentuk tabel. Hasil penelitian didapatkan 9 isolat yang mampu menghasilkan hormon AIA dengan kadar yang berbeda. Isolat penghasil AIA tertinggi yaitu isolat DT1 dengan kadar 114 ppm yang mempunyai karakteristik berbentuk bacil berwarna putih susu dan tidak berspora.     AIA hormone plays a role in enlarging and elongating cells, and cell division, especially at the tip of the plant. Bacteria that have the ability to produce IAA hormones include Enterobacter sp., Azospirillum sp., Klebsiella sp., Alcaligenes faecalis, Azoarcus sp., Serratia sp., Azotobacter sp., Cyanobacteria, Erwinia herbicola, Pseudomonas sp., Rhizobium, Bradyrhizobium, Agrobacterium tumafaciens. The synthesis of AIA requires an additional compound in the form of tryptophan. However, some bacteria can produce AIA without the addition of precursors. The goal of this study was to obtain isolates of AIA hormone-producing bacteria from the soil of the Liwa Botanical Gardens. This begins with the isolation of soil bacteria from the Liwa Botanical Gardens, then a quantitative test of AIA production capability is carried out without the addition of tryptophan. Qualitative testing of AIA production was carried out using Nutrien Broth media with spectrophotometric methods with the addition of Salkowsky reagent and observations were made after 72 hours of incubation. The data obtained are presented in tabular form. The results showed that 9 isolates were able to produce the AIA hormone at different levels. The highest AIA-producing isolate was the DT1 isolate with a concentration of 114 ppm which had the characteristics of a milky white bacillus and no spores.    

The Potential of Soil Bacterial Isolates from Liwa Botanical Gardens, West Lampung as Phosphate Solubilizing Bacteria

Tanah Kebun Raya Liwa (KRL) Lampung Barat merupakan tanah jenis laterit yang kandungan unsur hara dan kesuburan tanahnya rendah, sehingga tidak dapat mendukung pertumbuhan tanaman hias yang ada secara optimal. Salah satu unsur hara yang penting dalam menunjang kesuburan dan pertumbuhan tanaman adalah fosfat. Jumlah fosfat terlarut dalam tanah yang dapat dimanfaatkan oleh tanaman sangat sedikit sehingga menyebabkan defisiensi. Bakteri pelarut fosfat asli dibutuhkan untuk memenuhi kebutuhan fosfat bagi tanaman. Tujuan dari penelitian ini adalah untuk mendapatkan isolat bakteri pelarut fosfat yang berpotensi melarutkan fosfat. Penelitian ini dilaksanakan pada bulan Maret sampai Juni 2021 meliputi isolasi bakteri pelarut fosfat dan pengujian potensi pelarutan fosfat pada media pikovskaya padat. Potensi bakteri pelarut fosfat ditentukan berdasarkan nilai Indeks Kelarutan Fosfat (IPF) tertinggi. Hasil isolasi tanah dari Kebun Raya Liwa diperoleh 10 isolat yang mampu melarutkan fosfat dan menghasilkan zona bening. Isolat dengan potensi pelarutan fosfat terbaik adalah isolat C1 dan C3 dengan nilai indeks pelarutan fosfat 2, 6 dan 2.       Liwa Botanical Gardens (KRL) soil, West Lampung is a lateritic soil type nutrient content and low soil fertility, so it can’t support the growth of existing ornamental plants optimally. One of the important nutrients in supporting fertility and plant growth is phosphate. The amount of dissolved phosphate in the soil that can be utilized by plants is very small, causing a deficiency. Indigenous phosphate solubilizing bacteria are needed to meet the needs of phosphate for plants. The purpose of this study was to obtain isolates of phosphate solubilizing bacteria that have the potential to dissolve phosphate. This research was carried out from March to June 2021 covering the isolation of phosphate solubilizing bacteria and testing the potential for dissolving phosphate on solid pikovskaya media. Potential phosphate solubilizing bacteria were determined based on the highest Phosphate Solubility Index (IPF) value. The results of soil isolation from Liwa Botanical Gardens obtained 10 isolates capable of dissolving phosphate and producing a clear zone. Isolates with the best phosphate solubilizing potential were isolates C1 and C3 with phosphate solubilizing index values of 2, 6 and 2.    

DETECTION OF NITROGENASE PRODUCING BACTERIA FROM THE SOIL OF LIWA BOTANICAL GARDEN

Liwa Botanical Gardens is an ex-situ conservation area for various types of plants. Each plant produces organic matter that will provide nutrients for the growth of nitrogen-fixing bacteria. This indicates the existence of an environment that supports the growth of nitrogen-fixing bacteria. Nitrogen is one of the nutrients needed by plants for their growth. However, the abundance of nitrogen in the atmosphere cannot be utilized directly by plants but needs to transform into ammonium and nitrate first. This transformation can be done by nitrogen-fixing bacteria through an enzymatic process. This research aims to obtain bacterial isolates that can fix nitrogen. Nitrogen-fixing bacteria were isolated using Nutrient Agar (NA) medium and furthered by nitrogenase activity detection test with semi-solid Nitrogen Free Bromothymol Blue (NFB). Nitrogen-fixing bacteria are characterized by color changes in the medium. The results obtained 22 isolates with 3 isolates detected capable of producing nitrogenase enzymes, namely TBP B3, TB1 B2, and TMA2 B2

Lipolytic-screening of Bacillus genera as Biocontrol candidate In Coffee Plantation

Problems in decreasing coffee production one of them caused by plant pests attack. Countermeasures using pesticides and disinfectants are not effective because they have long effects and ruining the environment also pest resistance. It is necessary to prevent a more environmentally friendly way by utilizing a natural enemy in the form of a microorganism, the genus Bacillus. Lipase can hydrolyze lipids so that it can be used to degrade lipid substrates that compile the body structure of pests and diseases. This research aims to detect the lipolytic activity of Bacillus isolates from coffee plantations. The results of this research obtained 3 isolates of Bacillus namely T1, T2, and T3 which have differences in cell configuration and variations in the location of endospores. Furthermore, Bacillus isolates were detected lipolytic activity by growing isolates on lipase selective medium. Isolates that have the largest lipolytic activity are T2 isolate codes with an average index of 6.01 and the lowest lipolytic activity, namely, isolate T1 codes with an average index of 4.58