Journal of Tropical Biodiversity and Biotechnology

Nypa Palm Frond Degradation Utilizing Cellulolytic Lactic Acid Bacteria Isolated from Nypa Palm Worm (Namalycastis rhodochorde)

Rikhsan Kurniatuhadi, Tri Rima Setyawati, Ari Hepi Yanti, Albertus Williem — Tue, 08 Apr 2025 00:00:00 +0700

Cellulolytic lactic acid bacteria isolated from the gastrointestinal tract of nypa palm worms, namely NrLtC2, NrLtC4, and NrLtG2, exhibited cellulase enzyme activity in vitro. Cellulose degradation ability testing began on nipa palm frond fibers with variations in LAB type treatment and starter bacteria concentration (2%, 3.5%, and 5%) for 30 days. The results showed that the NrLtG2 bacterial isolate exhibited superior degradation ability compared to the other two isolates, resulting in a decrease in cellulose content of 20.14-26.39%. In contrast, the NrLtC2 and NrLtC4 isolates demonstrated lower degradation ability, with a range of 12.50-15.63%.

Whole-Genome Analysis and Tolerance Assessment on Bifidobacteria-like Bacteria Isolated from Breast Milk and Infant Fecal Samples in Indonesia

Fri, 11 Apr 2025 00:00:00 +0700

Probiotics are living microorganisms that can provide health benefits to the host when administered in sufficient quantities. To exert their health effects, probiotics must first be capable of surviving the harsh conditions of the gastrointestinal tract. We decided to sequence whole genomes of Bifidobacteria-like isolates (i.e., BS2-PS1, BS2-PS2, BS2-PB5, and BR2-12) and assess their abilities to resist low pH and bile salt. Molecular identification through whole genome sequencing indicated that the bacteria isolated from human breast milk were identified as Bifidobacterium breve (BS2-PS1 and BS2-PS2) and Lacticaseibacillus paracasei subspecies paracasei (BS2-PB5), whereas the bacteria isolated from infant feces was identified as Lactiplantibacillus plantarum (BR-12). All isolates exhibited resilience upon exposure to bile salts at concentrations of 0%, 0.3%, and 0.5%, with survival observed even at the highest concentration (0.5%) after three hours of incubation. The ability to withstand bile salt was presumably mediated by various genes that encode the resistance, e.g., bsh, cbh, dps, glf, cfa, or nagB, found in genomes of tested isolates. Upon exposure to pH 2 and 5 for three hours, BS2-PS1, BS2-PS2, and BR-12 exhibited acid resistance as well. The ability to withstand low pH could be mediated by the presence of relevant genes, e.g., argC, argH, dapA, pyk, pyrG, as well as genes that encode F₀F₁-ATPase enzyme, such as atpC, atpB, atpE, atpF, atpH, atpA, atpG, and atpD in their genomes. In summary, these results indicated the potential of all isolates to be further developed as probiotic candidates.

Assessing Indigenous Ureolytic Bacteria Isolated from Gua Damai Limestone for Microbially Induced Calcite Precipitation (MICP)

Mon, 14 Apr 2025 00:00:00 +0700

Low porosity and non-aggregated soil are significant global concerns, presenting substantial environmental hazards. This study determined the capacity of native ureolytic bacteria found in limestone to stabilise soil through the process of microbially induced calcite precipitation (MICP). Six pure bacterial isolates obtained from limestone in Gua Damai, Batu Caves, Selangor were qualitatively assessed for urease production. The isolate S4C4, identified as Bacillus tropicus strain NTF4, demonstrated the highest urease activity at 821.654 U mL^-1. This isolate precipitated 37.15 ± 9 mg mL^-1 of CaCO₃ after 96 hours of incubation and XRD analysis confirmed the biocementation of organic soils treated by B. tropicus strain NTF4, primarily forming calcite and vaterites. Significant calcite polymorph presence in soil samples is attributed to a longer treatment duration which promotes crystal development and stability. Harnessing indigenous limestone ureolytic bacteria with high urease activity presents a promising avenue for green soil bio-stabilisation. This approach potentially unlocks sustainable and scalable applications of microbial-induced calcite precipitation (MICP) in large-scale geo-engineering projects.