Bakteri sebagai salah satu agent penyubur tanah, masih sangat minim diketahui petani. Kenyataannya bakteri mampu menyediakan unsur hara makro yang dibutuhkan oleh tanaman, contohnya fosfat. Fosfat di tanah umumnya dalam bentuk terikat, baik yang berbentuk anorganik (Ca-P, Fe-P dan Al-P) maupun organik (asam nukleat dan fosfolipida). Mengeksresikan asam organik, merupakan cara umum bakteri untuk melarutkan fosfat terikat khususnya yang anorganik. Isolasi bakteri pelarut fosfat dilakukan di tanah rhizosper Kelapa Sawit (Eleis guineensis) PT Astra Agro Lestari dengan menggunakan media pikovskaya yang di dalamnya terdapat kalsium fosfat (Ca-P).  Hasilnya ada 6 bakteri yaitu A2, B5, C7, F1, F2, dan K1 yang mampu melarutkan kalsium fosfat (Ca-P). Uji kuantitatif dengan menggunakan spektrofotometer 410 nm, pada supernatant pikovskaya cair menunjukkan bakteri A2 mampu melarutkan fosfat 20,40 ppm paling baik jika dibandingkan dengan bakteri, C7= 7,69 ppm, F1= 5,77 ppm, F2= 5,53 ppm, B5= 1.19 ppm dan K1= 0,46 ppm. Identifikasi partial sequences 16s rRNA menunjukkan bakteri A2 putative Amycolatopsis albidoflavus.

This study aims to evaluate the effect of different tape yeast levels as inoculum in the banana peels fermentation process to the nutritional content. This study used an experimental method with a Completely Randomized Design (CRD) in one way ANOVA with 4 treatments and 4 replications. Treatments based on differences in the addition of tape yeast, all treatments were incubated for 6 days. The four treatments are (P0) Banana peel without the addition of yeast tape; (P1) Banana peel with the addition of yeast tape 1.5%; (P2) Banana peel with the addition of 3.0% yeast tape; (P3) Banana peel with the addition of 4.5% yeast tape. The measured variables were dry matter, crude protein, crude fat, crude fiber, calcium, and phosphorus content. Data were analyzed by analysis of variance and followed by Duncan's multiple range test to measure any significances. The results showed that the level of yeast tape significantly increased crude protein, crude fat, calcium and phosphorus (P<0.05), and significantly reduced crude fiber of banana peel (P<0.05. However the level of yeast tape has no significant effect on the dry matter content of banana peels. Conclusion tape yeast level of 4.5% can increase levels of crude protein, crude fat, calcium and banana skin phosphorus. The highest reduction in crude fiber in the use of yeast tape 3%.

Nitrogen is a macro nutrient needed by plants. Generally, people use inorganic fertilizers to fulfill nitrogen nutrients in plants. The problem then is, the continuous use of synthetic nitrogen fertilizers has a direct negative impact on the soil and a derivative impact on human health. The use of microorganisms, in this case bacteria, to provide nitrogen to plants can be done by isolating it and making it a biological fertilizer agent. Nitrogen fixing bacteria was isolated on the land of the oil palm plantation of PT Astra Agro Lestari. The isolated nitrogen-fixing bacteria were then tested quantitatively for their ability to fix nitrogen. The bacteria with the highest nitrogen fixing ability were then identified by sequencing their DNA nucleotide bases so that the bacterial strains were identified. The result is that there are 13 bacteria that are able to fix nitrogen with the codes J1, J3, Q5, L1, L11, J31, D1, M6, M5, R1, P2, J4 and C7. The quantitative test shows that bacteria with code D1 are the best at fixing nitrogen in the form of NH4, namely 0.27 ppm. The results of D1 bacterial DNA nucleotide base sequencing showed that the putitive Bacillus aerius strain 24K with identical values ​​and query cover reach