Plant Archives Volume 20 No. 2, 2020 pp. 4163-4168 e-ISSN:2581-6063 (online), ISSN:0972-5210 ISOLATION AND CHARACTERIZATION OF PHOSPHATE SOLUBILIZING BACTERIA FROM RHIZOSPHERE OF PINEAPPLE PLANTATION IN LAMPUNG, INDONESIA Kusuma Handayani 1 *, Nisa Rachmania Mubari 2 , Atang Sutandi 3 , Untung Sudadi 3 and Dwi Andreas Santosa 3 1* Study program of Soil Science, Graduate School, IPB University, Kampus IPB Dramaga, Bogor 16680, Indonesia. 2 Department of Biology, Faculty of Mathematics and Natural Sciences, IPB University, Kampus IPB Dramaga, Bogor 16680, Indonesia. 3 Department of Soil Science, IPB University, Kampus IPB Dramaga, Bogor 16680, Indonesia. Abstract Cultivation of pineapple (Ananas comosus) on a large scale plantation often use several fertilizers in high dosage. Utilization of rhizosphere microbes such as phosphate solubilizing rhizobacteria (rPSB) was expected to help reducing the dosage of inorganic P fertilizer application due to its capability in dissolving phosphate fixed by Al and Fe. By those, P become more available for plants. This study aims to evaluate the activity of rPSB isolated from pineapple plantation, both in fields/blocks of low and high pineapple production, in Lampung province. rBPF was isolated from pineapple plantation blocks with low (R) and high (T) production levels, as well as in the vegetative (V) and generative (G) stages of plant, with 5 replications. The results showed that the PSB population was around 10 3 CFU/g. Morphological characteristics of PSB isolates were mostly white, yellowish, gram-positive and rod-shaped. The optimum pH for average growth was at pH 5.0, while the optimum temperature was at 30°C. The five best isolates from each block were reconfirmed their phosphate solubility ability based on the phosphate solubility index (PSI). The best PSI of isolates in each block were TG3 (0.80), RV5 (1.05), TV1 (1.10) and RG2 (1.20). The increase in the amount of BPF from TV isolates to RV and TG to RG is in line with the increase in available P (Br- P) soil levels from 25.57 to 40.68 and from 23.83 to 25.25 ppm. This indicates increasing of PSB activity with the available P level of the soil. Based on 16S rRNA identification, isolate RG2 was similar 99.69% to Bacillus altitudinis. Key words: Bacillus altitudinis, P-Bray, molecular identification, phosphate solubility index. Introduction Activities of pineapple cultivation that have been carried out by plantations for many years have resulted in reducing quality of soil fertility. This can be caused by the use of fertilizers and pesticides in each pineapple growth cycle. Several inorganic fertilizers -such as Urea, K 2 SO 4 , CaCl 2 , DAP, MgSO 4 , Dolomite and borax- were used in pineapple cultivation processes by many plantations. The use of those fertilizers have caused soil hardening and reducing the soil fertility. According to previous research conducted by (Sherman and Brye, 2019), the physical properties of ultisol soils in the pineapple plantations are mostly in the low and very low qualities, so that some plantation blocks have low production levels. The difference in production levels caused by declining soil quality is one of the problem occurs, so it is necessary to study the presence of microbial species exist around the rhizosphere. In addition, it is also a need to study them at the different growth stages of plant. It is because according to a research conducted by (Sakimin et al., 2017), the need of fertilizer dosage in each phase of pineapple growth was different. The difference in dosage of fertilizer applied in the vegetative and generative phases will also affect the soil conditions. One of the most frequent efforts is adding potential phosphate solubilizing bacteria (PSB) as biological fertilizer (biofertilizer), e.g. Pseudomonas sp., Bacillus sp., B. megaterium and Chromobacterium sp. are PSB with high ability as biofertilizer, making P *Author for correspondence : E-mail: kusumahandayani@yahoo.co.id