Venty Suryanti

Novel colorimetric anion sensors based on N-acetylglyoxylic amides containing nitrophenyl signalling units.

N-acetylglyoxylic amides 4 and 5 bearing pendant 4-nitrophenyl and 2,4-dinitrophenyl groups respectively were synthesized and evaluated as anion sensors. A crystal structure of 4 was obtained by X-ray crystallography. Compounds 4 and 5 behaved as colorimetric sensors for CN(-) and F(-), and exhibited naked eye-detectable color changes upon the addition of these anions. The chromogenic properties of 4 and 5 were assessed by UV-Vis and (1)H NMR spectroscopy.

Self-assembly of alkyl N-acetylglyoxylic amides of varying chain lengths

Alkyl N-acetylglyoxylic amides have been synthesised from N-acetylisatins and their self-assembly studied in the solid state by X-ray crystallography. Different molecular conformations were observed for molecules 5a, 5b, 5d and 6b, which have a strong influence on their supramolecular organization in the crystals. Both strong and weak interactions played key roles in the self-assembly process and the formation of well-defined supramolecular architectures. Crystal structures of 5b revealed novel CO⋯CO (carbonyl–carbonyl) dipolar interactions involving three carbonyl groups and intermolecular halogen bonding interactions, either C–H⋯Br contacts with inclusion of cyclohexane in 5b-1 or Br⋯Br contacts without the inclusion of solvent in 5b-2.

Physicochemical Properties of Biosurfactant Produced by Pseudomonas fluorescens Grown on Whey Tofu

The research aims to examine the physicochemical properties of biosurfactant produced by Pseudomonas fluorescens. Biosurfactant was produced in whey tofu media containing 8 g/L nutrient broth and 5 g/L NaCl which was fermented for 2 days at room temperature. Biosurfactant was identified as rhamnolipids which had critical micelle concentration (CMC) value of 638 mg/L and surface tension of 54 mN/m. The biosurfactant had water in oil (w/o) emulsion type. The biosurfactant was able to decrease the interfacial tension more than 40% for emulsion of water with hexane, pentane, benzene, lubricants or kerosene. The stable emulsions were reached up to 30 days with the E24 value of about 50% when paraffin, toluene, lubricants or palm oil was used as an immiscible compound. Commercial surfactants, such as Triton X-100 and Tween-80 were investigated to compare their emulsification activities and emulsion stabilities with the produced biosurfactant.

Biosurfactant production by Pseudomonas fluorescens growing on molasses and its application in phenol degradation

A molasses based medium for the biosurfactant production by Pseudomonas fluorescens was developed, where the effect of pre-treated of molasses and medium composition were evaluated. Biosurfactant production was followed by measuring optical density (OD), surface tension and emulsifying index (E24) over 12 days of fermentation. The optimum condition for the biosurfactant production was obtained when a medium containing of 8 g/L nutrient broth, 5 g/L NaCl, 1 g/L NH4NO3 and 5% v/v pre-treated molasses with centrifugation was used as media with 3 days of fermentation. The biosurfactant was identified as a rhamnolipid type biosurfactant which had critical micelle concentration (CMC) value of 801 mg/L and was able to reduce the surface tension of the water from 80 mN/m to 51 mN/m. The biosurfactants had water in oil (w/o) emulsion type. Biosurfactant was able to emulsify various hydrocarbons, which were able to decrase the interfacial tension about 50-75% when benzyl chloride, anisaldehyde and palm oil were used as immiscible compounds. The biosurfactant exhibited the E24 value of about 50% and the stable emulsion was reached up to 30 days when lubricant was used as an immiscible compound. Up to 68% of phenol was degraded in the presence of biosurfactant within 15 days, whereas only 56% of phenol was degraded in the absence of biosurfactant. Overall, the results exhibited that molasses are recommended for the rhamnolipids production which possessed good surface-active properties and had potential application in the enhancement of phenol degradation.

Synthesis, Structures, and Conformations of Linked Bis-Glyoxylamides Derived from Bis-Acylisatins

A series of bis-glyoxylamides possessing hydrophobic alkyl chains was successfully synthesised by ring opening of bis-acylisatins with amines or amino acid alkyl esters. The crystal structures revealed the interplay of intra- and intermolecular interactions (NH···O and C=O···C=O interactions) and the conformations of these long molecules.

SUBSTITUSI IPTEKS PEMBESARAN LELE TEBAR PADAT

Petani pembesaran lele banyak yang mengeluh gagal dalam usaha pembesaran lele. Kegagalan tersebut disebabkan oleh penggunaan pakan dan kolam yang tidak efisien serta harga pakan mahal. Tujuan kegiatan pengabdian masyarakat ini memberikan wawasan tentang metode baru dalam usaha pembesaran lele yang menguntungkan. Mitra pengabdian kegiatan ini yaitu kelompok pembesaran lele Sungut Emas di Boyolali dan petani-petani pembesaran lele disekitarnya. Metode pengabdian dilakukan dengan metode substitusi ipteks secara teori, praktek lapangan, dan pendampingan. Substitusi ipteks secara teori meliputi penjelasan tentang pembesaran lele tebar padat dan aplikasi enzim dalam efisiensi pakan. Materi praktek lapangan meliputi cara persiapan air, cara pengelolaan air, cara menangani penyakit dan cara memberi pakan. Simpulan, substitusi ipteks pembesaran lele tebar padat mampu menyelesaikan masalah yang dihadapi petani pembesaran lele tebar padat sehingga keuntungan usaha meningkat.

Evaluation of biosurfactants grown in corn oil by Rhodococcus rhodochrous on removing of heavy metal ion from aqueous solution

The potential application of biosurfactants to remove heavy metal ion from aqueous solution by batch technique was examined. The glycolipids type biosurfactants were grown in a media containing of 20% v/v corn oil with 7 days of fermentation by Rhodococcus rhodochrous. The biosurfactants reduced the surface tension of water of about 51% from 62 mN/m to 30 mN/m. The biosurfactant increased the E24 of water-palm oil emulsion of about 55% from 43% to 97% and could maintain this E24 value of above 50% for up to 9 days. Heavy metal ion removal, in this case cadmium ion, by crude and patially purified biosurfactants has been investigated from aqueous solution at pH 6. Adsorption capacity of Cd(II) ion by crude biosurfactant with 5 and 10 minutes of contact times were 1.74 and 1.82 mg/g, respectively. Additionally, the adsorption capacity of Cd(II) ion by partially purified biosurfactant with 5 and 10 minutes of contact times were 0.79 and 1.34 mg/g, respectively. The results demonstrated that the adsorption cap...

Optimization of biosurfactant production in soybean oil by rhodococcus rhodochrous and its utilization in remediation of cadmium-contaminated solution

Biosurfactant production by Rhodococcus rhodochrous in soybean oil was developed, where the effect of medium composition and fermentation time were evaluated. The optimum condition for biosurfactant production was achieved when a medium containing 30 g/L TSB (tryptic soy broth) and 20% v/v soybean oil was used as media with 7 days of fermentation. Biosurfactant was identified as glycolipids type biosurfactant which had critical micelle concentration (CMC) value of 896 mg/L. The biosurfactant had oil in water emulsion type and was able to reduce the surface tension of palm oil about 52% which could stabilize the emulsion up to 12 days. The batch removal of cadmium metal ion by crude and partially purified biosurfactants have been examined from synthetic aqueous solution at pH 6. The results exhibited that the crude biosurfactant had a much better adsorption ability of Cd(II) than that of partially purified biosurfactant. However, it was found that there was no significant difference in the adsorption of Cd(II) with 5 and 10 minutes of contact time. The results indicated that the biosurfactant could be used in remediation of heavy metals from contaminated aqueous solution.