Endophytic bacteria are microorganisms that live in plant tissues and some of them contribute to nitrogen fixation for plants. This study aimed to isolate and identify endophytic bacteria from mangroves of Kutang Beach, Lamongan, which potentially as nitrogen fixing bacteria. Bacterial Isolates were used as candidates for biofertilizers. Leaves samples were taken from 10 sampling points. Bacterial isolation was initiated by sterilizing the surface of the leaves sample and grinding it aseptically. Isolation was carried out with a pour plate method on Nutrient Agar medium. Screening for endophytic bacteria's potential as N-fixing agent was carried out by growing the bacterial isolates on a semi-solid Nitrogen Free Bromothymol Blue (NFB) medium. The isolates that produced a positive reaction with a change in the color of the medium to blue were then subjected to macroscopic (shape, color, elevation, and the edge of the colony) and microscopic observations (Gram stain and bacterial cell measurements). The isolates showed the fastest change in the color of the medium were identified by the molecular marker of the 16S rRNA gene. The data obtained were analyzed descriptively. As many as 20 isolates were obtained from the mangroves of Kutang Lamongan Beach, and ten isolates of twenty potentially as nitrogen-fixing bacteria. The ten nitrogen-fixing bacteria isolates had varying macroscopic characteristics. The microscopic characteristics showed that eight isolates had Gram-positive bacilli, and two isolates were Gram-negative with varying bacterial sizes. Based on the 16S rRNA gene sequence, the most potential of nitrogen-fixing bacteria was LMG II-14 isolate and identified as Paenibacillus alvei LMG II-14 with 99.36% similarity to Paenibacillus alvei strain DSM 29 based on the NCBI database. The ten nitrogen fixing isolates that have been obtained can later be used as candidates for biofertilizer composition, especially Paenibacillus alvei LMG II-14.
Most of the plant-associated bacteria can synthesize active biological components of phytohormones such as auxin. This study aimed to examine the potency of 61 endophytic bacteria isolates from the mangroves at Kutang Beach, Lamongan in producing IAA hormone and to identify types of isolates effecting the concentration of IAA, morphological characteristics of isolates, as well as endophytic bacterial species that have the most potential to produce IAA hormone. Screening of endophytic bacteria isolates was performed using the colorimetric method and the production of IAA was carried out using the spectrophotometric method. IAA production by endophytic bacteria was analyzed descriptively and statistically. One-Way ANOVA was employed to determine the effect of the isolate type on the concentration of IAA. The most potential isolates to produce IAA hormone are identified by 16s rRNA gene marker. The screening results showed that 12 isolates of endophytic bacteria have the potential to produce IAA hormones (2.0-9.3 ppm), coded with LMG 7, 15, 31, 32, 43, 53, 54, 55, 56, 57, 62, and 63. The results of the One-Way ANOVA test suggested that the type of isolates did not affect the concentration of IAA produced by endophytic bacteria. The twelve isolates had different morphological characters and those were Gram-positive bacilli with cell sizes ranging from 1.5 µm - 3 µm. The highest concentration of IAA was produced by LMG 15 (9.3 ppm). LMG 15 was identified as Bacillus cereus strain LMG 15, having 99.33% similarity to Bacillus cereus strain IAM 12605.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.