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INDONESIA
EKSAKTA: Journal of Sciences and Data Analysis
Published by Universitas Islam Indonesia
ISSN : 27160459     EISSN : 27209326     DOI : 10.20885
Core Subject : Science, Engineering,
Chemical Engineering, Chemistry & Bioengineering Chemistry Earth & Planetary Sciences Materials Science & Nanotechnology
Ekstakta is an interdisciplinary journal with the scope of mathematics and natural sciences that is published by Fakultas MIPA Universitas Islam Indonesia. All submitted papers should describe original, innovatory research, and modelling research indicating their basic idea for potential applications. The Journal particularly welcomes submissions that focus on the progress in the field of mathematics, statistics, chemistry, physics, biology and pharmaceutical sciences.
Arjuna Subject : Kimia(semua kategori) - Kimia (Lain-Lain)
Articles 12 Documents
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Search results for , issue "VOLUME 7, ISSUE 1, April 2026" : 12 Documents clear
Effect of Phenol–Formaldehyde Molar Ratio on the Physicochemical Properties of Phenolic Synthetic Tanning Agent (Syntan) Winata, Wahyu Fajar; Hermawan, Prasetyo; Nurbalia, Elis
EKSAKTA: Journal of Sciences and Data Analysis VOLUME 7, ISSUE 1, April 2026
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20885/EKSAKTA.vol7.iss1.art10

Abstract

Phenolic synthetic tanning agents (syntans) are widely used in the leather industry due to their controllable properties and consistent performance. This study aims to investigate the effect of phenol– formaldehyde molar ratio on the physicochemical properties of syntans synthesized via sulfonation. The syntans were prepared using various molar ratios (0:1, 0.5:1, 1:1, 1.5:1, 1:0.5, and 1:0) throughcondensation followed by sulfonation. The products were characterized in terms of pH, specific gravity, viscosity, degree of sulfonation (DS), and functional groups using FTIR spectroscopy. The results show that increasing phenol or formaldehyde concentration led to higher specific gravity and viscosity, indicating increased polymerization. The pH values ranged around ~4, confirming suitability for leather processing. The DS decreased with increasing phenol or formaldehyde concentration, suggesting competition between polymerization and sulfonation reactions. The optimal molar ratio (1:1) produced the most homogeneous and stable syntan system. The pH values of all syntans were consistently around ~4, indicating suitability for leather processing. Increasing phenol or formaldehyde concentration resulted in higher viscosity and specific gravity, while the degree of sulfonation decreased significantly, confirming the trade-off between polymerization and sulfonation reactions. In conclusion, the phenol–formaldehyde molar ratio significantly influences syntan properties by controlling the balance between polymerization and sulfonation. These findings provide a scientific basis for optimizing syntan formulation and improving efficiency in sustainable leather processing.
Production of Protease Enzymes and Bioactive Compounds by Lactic Acid Bacteria (LAB) From Broccoli (Brassica oleracea L.) Using Lactobacillus plantarum Starter Hidayat, Habibi; Maharani, Najlaa Ayu; Maulani, Qisti; Fajarwati, Febi Indah
EKSAKTA: Journal of Sciences and Data Analysis VOLUME 7, ISSUE 1, April 2026
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20885/EKSAKTA.vol7.iss1.art12

Abstract

This study aimed to isolate and characterize Lactic Acid Bacteria (LAB) from broccoli (Brassica oleracea L.) with potential protease-producing activity and probiotic properties. Fermentation was carried out using Lactobacillus plantarum as a starter culture. The obtained LAB isolates were subsequently evaluated for protease activity and analyzed for bioactive compound content. The results demonstrated that LAB isolates obtained from broccoli were capable of producing proteases with significant activity, indicating their potential for biotechnological applications. In addition, the isolates produced bioactive compounds exhibiting antibacterial activity against several pathogenic bacteria, including S. epidermidis, K. pneumoniae, E. coli, S. aureus, S. typhi, and S. pyogenes, as evidenced by the formation of inhibition zones. The isolate demonstrated strong antibacterial activity against all tested pathogens with inhibition zones of 56 mm for S. epidermidis, 30 mm for S. typhi, 12 mm for both K. pneumoniae and E. coli, and 11 mm for S. pyogenes and S. aureus. Acid tolerance assays demonstrated that the LAB isolates survived at low pH, and protease activity assays showed that the isolate produced an enzyme with proteolytic activity of 23.5 mm and 0.0440 U/mL.

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