Modifikasi Medium Menggunakan Saline-Water Soluble Fraction (SSF) atau Fraksi Minyak Terlarut untuk Menumbuhkan Bakteri Pendegradasi Hidrokarbon

Isolasi bakteri pendegradasi hidrokarbon memerlukan teknik yang baik dan nutrisi optimal untuk pertumbuhannya. Kendala dalam pembuatan medium dan pengamatan isolat bakteri yang mengandung hidrokarbon sering terjadi di laboratorium, sehingga dibutuhkan teknik pengembangan metode dalam proses isolasi bakteri pendegradasi hidrokarbon. Penelitian ini bertujuan untuk mengetahui dan membandingkan jumlah dan jenis koloni bakteri yang tumbuh dalam medium Zobell+saline-water soluble fraction (SSF) dibandingkan dengan medium Zobell+minyak bumi. Metode penelitian yaitu mengisolasi bakteri menggunakan medium Zobell+SSF 6 jam (A), 12 jam (B), 24 jam (C) dan sebagai kontrol adalah medium Zobell+1% v/v minyak bumi (K), perhitungan bakteri menggunakan metode TPC dan mengidentifikasi bakteri dengan alat VITEK-MS. Hasil penelitian memperlihatkan bahwa jumlah bakteri yang tumbuh pada medium Zobell+SSF 24 jam (C) adalah 6.9 x 108 CFU/ml, hal ini menunjukkan lebih baik dibandingkan dengan Zobell+1% v/v minyak bumi (K)=5.2 x 108 CFU/ml, medium Zobell+SSF 12 jam (B)=6.6 x 107 CFU/ml dan medium Zobell+SSF 6 jam (A)=1.8 x 107 CFU/ml.Kesimpulan penelitian ini adalah bahwa dari segi jumlah total bakteri medium modifikasi Zobell+SSF pengadukan selama 24 jam (C) lebih baik dalam menumbuhkan bakteri pendegradasi hidrokarbon dibandingkan dengan pengadukan 6 jam (A), 12 jam (B), dan medium Zobell+1% v/v minyak bumi (K). Sedangkan apabila berdasarkan dengan keragaman bakteri, didapatkan hasil bahwa strain bakteri yang terisolasi pada medium modifikasi Zobell+SSF perlakuan pengadukan 6, 12, 24 jam sama dengan strain bakteri yang tumbuh pada kontrol (medium Zobell +1% v/v minyak bumi. Bakteri yang teridentifikasi sebagai bakteri pendegaradsi hidrokarbon adalah bakteri Klebsiella pneumoniae, Enterobacter asburiae/Enterobacter cloacae dan Pseudomonas aeruginosa.

Oxidation Characteristics of Water Soluble Fractions of Agro-Stalks with Focus on Function of Reactive Inorganics

In order to deepen the understanding of the thermochemical behavior of reactive inorganics, which play an important role in slagging and fouling during combustion of agro-stalks, the oxidation behavior of the water-soluble fraction of corn stover, wheat straw and rice straw was examined using a simultaneous thermogravimetric analyzer. The oxidation characteristics were discussed in combination with elemental analysis of water-soluble fractions. Results showed that reactive inorganics elements account for 30–40% in water-soluble fractions of the three agro-stalks and carbon was oxidized at two separate stages. Four stages were found during oxidation of water-soluble fractions – (1) devolatilisation of organics (100‒400 °C); (2) oxidation of char (400–650 °C); (3) oxidation of char with melting of salts or decomposition of carbonate (650–800 °C); (4) vaporization of KCl (800–1000 °C). This work provides a base study for an optimized design of combustion for agro-stalks and pharmaceutical waste.

Use of the pK Spectroscopy Method in the Study of Protolytic Properties of Humic Substances and Other Soil Polyelectrolytes

A common technique for the potentiometric analysis of complex protolytic systems is mathematical data processing. This approach allows for transforming the experimental titration curve into a function of the ionogenic group distribution of the titrated object by the values of the pK (−lgKa) acid dissociation. This distribution function is called the pK spectrum, and the approach itself is called pK spectroscopy. In this case, solutions are found not in the form of discrete dissociation constants but as a distribution function of the concentrations of ionogenic groups over a continuous spectrum of dissociation constants. The purpose of this work is to test the possibility of using the pK spectroscopy method for assessing the acid–base properties of humic substances, water-soluble fraction, and soils. The results of testing the pK spectroscopy method showed that this method is expressive and more informative than the traditional method of continuous potentiometric titration. The use of the pK spectroscopy method for studying the protolytic properties of humic substances and other environmental objects is justified. The content and values of pK of ionogenic groups of fulvic acids, water-soluble fraction, and soil suspensions were determined. In the objects, the presence of three to five ionogenic groups with pK values from 3.2 to 9.6 was revealed.

Nanocellulose from citrus processing waste using water and electricity only

Along with a water-soluble fraction rich in pectin, the hydrodynamic cavitation of citrus processing waste carried out in water directly on a semi-industrial scale affords an insoluble fraction consisting of a new nanocellulose of high quality. Lemon and grapefruit nanocellulose powders isolated upon filtration and mild drying consist, respectively, of 100-500 nm wide cellulose nanorods, and of 500-1,000 nm wide ramified microfibrils extending for several μm. The process is general and can be applied to any citrus processing biowaste. These findings establish a long-sought technically viable route to a material whose numerous potential applications in fields ranging from biomedicine to composite production have been limited by the harsh conditions required for the extraction of nanocellulose via acid or enzymatic hydrolysis following pretreatment of lignocellulosic biomass with acid-chlorite or alkali.