The ability of raw and dried Sargassum duplicatum to remove methylene blue (MB) from aqueous solution was evaluated. Brown algae. S. duplicatum before and after MB adsorption was characterised by Fourier transform infrared spectroscopy (FT-IR). Batch experiments were conducted to examine the effects of parameters such as initial pH, biomass dosage, contact time, and initial dye concentration on MB Adsorption. The optimum adsorption was found at around pH 5, adsorbent dosage 1 g/L, and initial concentration of MB at 20 mg/L. Adsorption occurs very fast in first 5 min and reaches the equilibrium at 70 min. The maximum percentage of dye removal was 88,9%. This study suggests that S. duplicatum has good potential capacity to remove MB dye and could offer promising opportunity as a low-cost biosorbent.

No abstract

Penelitian ini bertujuan untuk mengetahui karakteristik serta aktivitas antibakteri asap cair yang berasal dari biomassa kayu putih (Melaleuca leucadendra) dan kayu jati (Tectona grandis). Asap cair dalam penelitian ini diperoleh melalui kondensasi asap yang dihasilkan dari pirolisis biomassa kayu putih dan kayu jati pada suhu 250°C selama 8 jam. Asap cair yang terbentuk dari kedua biomassa memiliki karakteristik warna cokelat transparan, pH 2,8 (asam), dan masih memiliki bahan padatan terapung. Hasil uji antibakteri asap cair dari kayu putih dan kayu jati dengan metode difusi agar terhadap tiga (3) isolat bakteri patogen yaitu Escherichia coli FNCC 194, Staphylococcus aureus FNCC 0047, dan Pseudomonas aeruginosa FNCC 0156 menunjukkan hasil positif dengan terbentuknya zona jernih di sekeliling cakram. Hasil uji antibakteri asap cair dari biomassa kayu jati terhadap Staphylococcus aureus FNCC 0047 menunjukkan perbedaan yang signifikan dibandingkan dengan kontrol positif, yaitu Ampicillin 10 mcg. Karakterisasi fisik dan analisis GC-MS digunakan untuk mengetahui komposisi asap cair yang berasal dari dua biomassa yang berbeda. Diketahui bahwa acetic acid merupakan komponen utama yang ditemukan pada kedua sampel, yaitu sebesar 45,35% pada asap cair dari biomassa kayu putih dan 25,35% pada asap cair dari biomassa kayu jati. Selain acetic acid, kandungan fenol juga ditemukan pada kedua asap cair. Asap cair dari biomassa kayu putih mengandung fenol sebesar 6.53%, sedangkan asap cair dari biomassa kayu jati mengandung fenol sebesar 11.19%. Tingginya kandungan fenol yang dimiliki asap cair dari biomassa kayu jati diduga turut berpengaruh terhadap kemampuannya dalam menghambat pertumbuhan bakteri.

Liquid smokes result from the process of pyrolysis of biomass as a raw material which generally contains high content of lignin, cellulose, and hemicellulose. The phenolic compounds, acid compounds, and carbonyl compounds are the main components in liquid smoke and show antioxidant activity. One of the potential raw materials from industrial's waste that has potentiality as liquid smoke is wood sawdust. Phenolic compounds that can be found as a prevalent composition in wood sawdust have antioxidant activity and it is potential to be used as a material for food preservation to maintain freshness and extend product shelf life. The manufacture of liquid smoke from biomass is carried out through several stages, starting from burning biomass at high temperatures (pyrolysis), condensation, and ending up with purification. The purification stage aims to remove toxic compounds resulting in purified products. The present study aimed to evaluate the crude and purified liquid smoke derived from wood sawdust and its phenol composition. Investigation of phenol compound was conducted by Folin-Ciocalteu method and Gass-Chromatography Mass Spectroscopy for further analysis. The crude and purified liquid smoke's antioxidant presented 46.24 µg/ml and 1404.89 µg/ml respectively. Regarding the total phenolic content, the phenol content in crude liquid smoke was 95.93 µgGAE ± 1.15 µgGAE whereas the phenol content on purified liquid smoke was 39.27 ± 2.67 µgGAE. Finally, there were approximately seven phenolic compounds observed in gas chromatography-mass spectrometry analysis. Among the detected compound, Phenol (CAS) Izal and Phenol, 2-methoxy-(CAS) Guaiacol were found as dominant phenolic compounds both in crude and purified liquid smoke. This study proved that high phenolic compounds in crude liquid smoke had the effectiveness for observed antioxidant properties against free radicals.

Pyrolysis of cajuput ( Melaleuca leucadendron ) twigs and rice ( Oryza sativa ) husks to produce liquid smoke and antibacterial activities of the liquid smoke fractions were investigated. The liquid smoke was produced by pyrolysis at 500 °C for 8 h and contained fine chemicals, such as acetic acid, carbonyl, cyclic ketones, and phenolic compounds with pH 2.1–2.9. The liquid smoke was separated by vacuum evaporation under vacuum conditions at low temperatures (40 °C, 50 °C, and 60 °C) to recover three fractions. The composition of each fraction influenced its antibacterial activities. Antibacterial activities of the liquid smoke fractions were tested against Gram-positive bacteria ( Listeria monocytogenes , Bacillus subtilis , and Staphylococcus aureus ) and Gram-negative bacteria ( Salmonella typhimurium , Pseudomonas aeruginosa , and Escherichia coli ). Whole fractions of the liquid smoke inhibited the six pathogenic bacteria, with the inhibition zone larger or smaller than the positive control. Among the liquid smoke fractions, the liquid recovered at 60 °C for the cajuput twigs and rice husks demonstrated a stronger inhibitory effect on bacterial growth than the other fractions.