Exploration of vitamin B12-producing bacteria from Indonesia Eutrophic Lake: A new strategy to improve microalgae biomass production

Prabaningtyas S, Ardyati T, Suharjono, Retnaningdyah C. 2021. Exploration of vitamin B12-producing bacteria from Indonesia Eutrophic Lake: A new strategy to improve microalgae biomass production. Biodiversitas 22: 4538-4544. Biofuel producing autotrophs and heterotrophs organisms are mostly found in freshwaters such as lakes. Preliminary research showed that Ranu Grati has a high diversity of microalgae and bacteria. Microalgae are known as one source of biofuels due to the high content of lipid. The growth of microalgae is strongly influenced by vitamin B12, which is synthesized by bacteria. The role of vitamin B12 in the metabolism of algae is mainly as a co-enzyme for vitamin B12-dependent methionine synthase. The purpose of this research was to observe the bacterial diversity based on NGS analysis, to explore vitamin B12 produced by bacteria from Ranu Grati lake, and also to identify the highest potency of vitamin B12-producing bacteria based on 16S rRNA gene sequencing. The study was carried out by taking a water sample at a depth of 50 cm at five stations. Isolation of total bacterial DNA was carried out using FastDNA Spin Kit for Soil. The metagenomic method of Next Generation Sequencing (NGS) was used as an initial study of bacterial diversity. Vitamin B12-producing bacteria was isolated using PYBG agar (phytone peptone, trypticase peptone, lab-lemco powder, bacto yeast extract, glucose, agar). Isolated bacteria were screened for production of vitamin B12. The potential isolates were identified base on 16S rRNA gene sequence similarity. The results of the metagenomic study showed that the genus of potential bacteria producing vitamin B12 included Bacillus, Pseudomonas, Propionibacterium, Enterobacter, Escherichia, Acinetobacter, and Flavobacterium. The results of screening with PYBG media obtained 30 isolates of vitamin B12 producing bacteria. Ten efficient vitamin B12-producing isolates were identified as Lysinibacillus fusiformis (isolate G2V1), Bacillus cereus group (isolate G2V25, G2V24, G2V13, G2V9, G2V8), Alcaligenes faecalis (isolate G2V22), Delftia acidovorans (isolate G2V14A) and the genus Delftia (isolate G2V19). The isolate G2V1 (Lysinibacillus fusiformis) was the highest producer of vitamin B12 which was able to produce 33,783 ug/mL of vitamin B12 at 4 days incubation time.

Isolation, Characterization and Identification of a New Lysinibacillus fusiformis Strain ZC from Metlaoui Phosphate Laundries Wastewater: Bio-Treatment Assays

The aim of the present study is to isolate, characterize and identify a novel strain ZC from the Metlaoui phosphate laundries wastewater (MPLW). The chemical characterization of this phosphate rich effluent showed an alkaline pH and is saline, highly turbid and rich in suspended matter and total solids. The MPLW samples were loaded with potentially toxic metals, presented in decreasing order as follows: magnesium (5655 mg L−1), potassium (45 mg L−1), lead (1 mg L−1), iron (0.7 mg L−1), cadmium (0.5 mg L−1), copper (0.3 mg L−1) and zinc (0.1 mg L−1). Due to the high COD/BOD5 ratio, a poorly biodegradable organic load is underlining. The newly isolated strain was identified as Lysinibacillus fusiformis using 16S rDNA sequencing analysis. The viability of this new strain was tested in presence of the zinc, lead, cadmium, manganese and copper at 1, 10 and 100 mM. The L. fusiformis survival, under metallic stress, was inversely proportional to metal ion concentrations, while lead and zinc were the most toxic ones using MTT assay. Then, the newly isolated strain was characterized in terms of enzyme production, proteomic alteration and antibiotic resistance. The strain ZC revealed some modifications in the biochemical and enzymatic profiles by either the appearance or/and the disappearance of some activities. In addition, the increase in metal ions stress and concentrations was proportional to the adherence and to the hydrophobicity. The presence of the metal ions suggested the change of sensitivity to the resistance of this strain towards tobramycin, kanamycin, neomycin, netilmicin and cefoxitin, showing an increase in the MARindex. The strain ZC, used as a biological tool for MPLW treatment, showed a reduction in the metal ion contents. This reduction was due to accumulation and/or adsorption, showing a bioprocessing performance of the newly isolated L. fusiformis.

Biodegradation of polypropylene films by Bacillus paralicheniformis and Lysinibacillus fusiformis isolated from municipality solid waste contaminated soil

The fossil fuel or petroleum derived plastics are applied in our routine life because of their easy availability. Distribution and contamination of the plastics in the landfills are the major reasons for these biodegradation study. This current study reveals the biodegradation of polypropylene films and the growth of Bacillus paralicheniformis and Lysinibacillus fusiformis isolated from plastic contaminated soil collected from municipality solid waste management site. The degradation rate of PP films was confirmed by the results of biodegradation analysis. The growth of Bacillus paralicheniformis and Lysinibacillus fusiformis had shown OD values at 600nm after the degradation period of 4 weeks increasing from 0.131 to 0.334 and 0.148 to 0.213 respectively. The viable cell count increased from 8×104cells/ml to 12×104cells/ml and 10.1×104 cells/ml to 15.2×104 cells/ml respectively. The physical and chemical changes of PP films were confirmed by FT-IR and XRD analysis. These analysis confirmed that the bacterial strains have the ability to change the chemical and physical nature of PP films and can utilize the PP films as sole carbon source.

Acetic Acid-Producing Endophyte Lysinibacillus fusiformis Orchestrates Jasmonic Acid Signaling and Contributes to Repression of Cadmium Uptake in Tomato Plants

Diverse signaling pathways regulated by phytohormones are essential for the adaptation of plants to adverse environments. Root endophytic bacteria can manipulate hormone-related pathways to benefit their host plants under stress conditions, but the mechanisms underlying endophyte-mediated plant stress adaptation remain poorly discerned. Herein, the acetic acid-producing endophytic bacteria Lysinibacillus fusiformis Cr33 greatly reduced cadmium (Cd) accumulation in tomato plants. L. fusiformis led to a marked increase in jasmonic acid (JA) content and down-regulation of iron (Fe) uptake-related genes in Cd-exposed roots. Accordantly, acetic acid treatment considerably increased the JA content and inhibited root uptake of Cd uptake. In addition, the Cr33-inoculated roots displayed the increased availability of cell wall and rhizospheric Fe. Inoculation with Cr33 notably reduced the production of nitric oxide (NO) and suppressed Fe uptake systems in the Cd-treated roots, thereby contributing to hampering Cd absorption. Similar results were also observed for Cd-treated tomato plants in the presence of exogenous JA or acetic acid. However, chemical inhibition of JA biosynthesis greatly weakened the endophyte-alleviated Cd toxicity in the plants. Collectively, our findings indicated that the endophytic bacteria L. fusiformis effectively prevented Cd uptake in plants via the activation of acetic acid-mediated JA signaling pathways.

Biocontrol potential of bacterial isolates from vermicompost and earthworm against the root-knot nematode Meloidogyne javanica infecting tomato plants

Background Root-knot nematodes (Meloidogyne spp.) are the most destructive agricultural pests, which parasitize thousands of different plant species in the world. Using antagonistic bacteria can be a potential alternative to hazardous chemical nematicides. This study was conducted to evaluate the biocontrol activities of the bacteria isolated from vermicompost and earthworm against M. javanica in infected tomato plants. Results Seventeen bacteria were isolated from vermicompost and earthworm. Their antagonistic effects were tested against the root-knot nematode M. javanica in laboratory and in glasshouse experiments. In the preliminary screening test, 8 bacterial isolates significantly caused more than 50% decrease in reproduction factor (Rf) of the nematode on tomato plants. Six isolates with more than 60% reduction in the nematode Rf were selected and identified as follows: Lysinibacillus fusiformis C1, Bacillus megaterium C3, B. safensis VW3, Pseudomonas resinovorans VW4, Lysinibacillus sp. VW6, and Sphingobacterium daejeonense LV1 by 16S rRNA gene sequencing. The isolates B. megaterium C3, B. safensis VW3, P. resinovorans VW4, and L. fusiformis C1 inhibited the nematode egg hatching by 20–28%, and Lysinibacillus sp. VW6 and L. fusiformis C1 caused 15 and 20% mortality of the second-stage juveniles in vitro. In a glasshouse, the 6 bacterial isolates reduced the nematode Rf by 47–66%, and P. resinovorans VW4 was the most effective isolate. However, B. safensis VW3, B. megaterium C3, and L. fusiformis C1 had the best effect on plant growth. Conclusions Most of the bacteria isolated from earthworm or vermicompost had nematicidal properties. This study provided empirical evidence of the nematicidal potential of isolates Lysinibacillus fusiformis C1, Pseudomonas resinovorans VW4, and Sphingobacterium daejeonense LV1 and the antagonistic activities of Bacillus megaterium C3 and B. safensis VW3 against Meloidogyne javanica.