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All Journal Jurnal Ilmiah RESPATI Biosaintifika: Journal of Biology & Biology Education
Ruhimat, Riki
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Agriculture, Biological Sciences & Forestry

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Selection of Potential Lignin-Degrading Bacteria and Fungi Isolates from the Gunung Lumut and Sungai Wain in East Kalimantan Ruhimat, Riki; Kumala Dewi, Tirta; Noviana, Zahra; Sutisna, Entis; Mulyani, Nani; Juwari, Micha; Sufaati, Supeni; Antonius, Sarjiya; Verchius, Eric
Biosaintifika: Journal of Biology & Biology Education Vol. 17 No. 1 (2025): April 2025
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/biosaintifika.v17i1.14755

Abstract

The enzymes laccase (Lac), manganese peroxidase (MnP), and lignin peroxidase (LiP) are ligninolytic enzyme groups that have a crucial role in degrading lignin compounds. These complex components are abundant in plant biomass. This research aims to isolate and characterize microorganisms producing the enzymes Lac, MnP, and LiP from leaf litter, rhizosphere soil, and sediment in the Gunung Lumut Protected Forest (GLPF) and Sungai Wain Protected Forest (SWPF), East Kalimantan. The bacterial and fungal isolates obtained were cultured on NA and PDA media enriched with 0.05% guaiacol as a substrate. Initial selection was carried out based on the colony growth rate and the formation of a brownish discoloration zone, which indicates ligninolytic enzyme activity. The superior isolates were then tested for extracellular enzyme activity quantitatively using a UV-Vis spectrophotometer. Among the bacterial isolates, the highest Lac activity is isolated GLS 5.1.2 (173.44 U L-1); the highest MnP activity is isolated GLS 5.3 (177.41 U L-1); and the highest LiP activity is isolated GLS 5.1.2 (1034.05 U L-1). In the group of fungi, isolate SS2 was detected with the highest Lac activity (20.66 U L-1), MnP activity (333.75 U L-1), and LiP activity (2516.13 U L-1). Biodiversity sources in the Gunung Lumut Protected Forest (GLPF) and Sungai Wain Protected Forest (SWPF), East Kalimantan have the potential to produce microbial isolates with unique enzymatic characteristics that have never been reported before. The resulting microbial isolate can be used as a bioactivator in composting organic waste to produce high-quality organic fertilizer.
Artikel Review: Produksi dan Aplikasi α-Amilase Bakteri Psikrofilik di Bidang Pangan Nurjasmi, Reni; Aprilia, Sarah; Ruhimat, Riki; Rahmatullah, Rifki
JURNAL PERTANIAN Vol 16, No 3 (2025): Jurnal Ilmiah Respati
Publisher : Universitas Respati Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.52643/jir.v16i3.7421

Abstract

Psychrophilic bacteria have been widely found in extreme low-temperature environments such as the Arctic and Antarctic oceans and glacial lakes. Some of these bacteria possess the hydrolytic enzyme α-amylase, which functions to hydrolyze starch into simple sugars such as maltose, maltotriose, and glucose. The structure of psychrophilic α-amylase is highly flexible due to reduced hydrophobic interactions and an increased number of hydrophilic residues. This unique structure allows the enzyme to function optimally at low temperatures, specifically 0–20 °C. High-quality enzymes can be obtained through integrated production stages, including the isolation of psychrophilic bacteria, low-temperature fermentation, and stepwise purification. Response Surface Methodology is often employed to achieve high yet economical enzyme yields. The enzyme isolated from psychrophilic bacteria is purified through ammonium sulfate precipitation, dialysis, and several chromatographic techniques performed sequentially to obtain a pure enzyme ready for characterization. Biochemical characterization reveals high enzyme activity at low temperatures, an optimal pH range of 6.5–8.0, and a strong dependence on calcium ions to maintain structural stability. Kinetic analysis shows that psychrophilic α-amylase has a low Michaelis constant (Km), indicating high substrate affinity that enables optimal performance even when substrate availability is limited. These advantages are widely utilized in various fields, particularly the food-processing industry, such as syrup production, baking, fermented beverages, and frozen-food processing. The ability of α-amylase to function at low temperatures provides significant benefits for food processing because it reduces energy requirements, thereby lowering production costs. The application of psychrophilic α-amylase also offers a promising solution for achieving environmentally friendly food-processing industries.
Co-Authors Aprilia, Sarah Entis Sutisna Juwari, Micha Kumala Dewi, Tirta Mulyani, Nani Rahmatullah, Rifki Reni Nurjasmi, Reni Sarjiya Antonius Supeni Sufaati Verchius, Eric Zahra Noviana