This paper, for the first time, reports the optimization of the critical medium components for bio-surfactant production from achromobacter xylos strain GSR21 using statistical experimental design. Response surface methodology (RSM) was employed to determine the optimal levels of process variables (agar powder, yeast extract, FeSO₄7H₂O, and KH₂PO₄). Central composite design (CCD) of RSM was used to study the four variables at five levels, and bio-surfactant concentration was measured as response. Regression coefficients were calculated by regression analysis, and the model equation was determined. R² value for bio-surfactant (g/L) was tested to be 0.7222, indicating that the model fitted well with the experimental results. Verification of the mathematical model was conducted by performing the experiment with the predicted optimized values, and bio-surfactant yield was found to be 9.69 g/L. Validation of the predicted model was fitted 96.9% with the experimental results conducted under the optimum conditions. Agar powder and yeast extract was identified as efficient components for bio-surfactant (achromobacter xylos GSR21) production.

Fly ash is considered as an under-utilized product of pulp and paper industry and is mainly land-filled. However, it can be repurposed as an adsorbent for organics of wastewater effluents. Despite efficient adsorption capability, its metal components may dissolve in wastewater and harm the environment. This investigation focused on the leaching behavior of metals from biomass-based fly ash in water at pH 6 and 12.5. A similar investigation was performed in the spent liquor of a pulping process to evaluate the extraction of metals from fly ash in such an environment that fly ash could be used as an adsorbent. The results revealed that the predominant metals leached from fly ash in water and the spent liquor were Ca, K, Mg, Mn, Na, and Si. The trace metals including Al, Ba, Sr, and Zn were also detected to a significant extent. Interestingly, the extraction of metals from fly ash in spent liquor was more limited than in water, which is beneficial for the application of fly ash in spent liquors.

Starch nanoparticles are used as a matrix with natural rubber for tire making, alternative adsorbents for wastewater treatment, drug carriers, packaging materials, emulsion stabilizers and fat replacers. The objective of this study is to prepare the starch nanoparticles from cassava peel by mineral acid hydrolysis using hydrochloric and sulfuric acids and perform the characterization of starch nanoparticles with Fourier transform infrared (FTIR),X-ray diffraction (XRD) and scanning electron microscope (SEM)It was found that the obtained yield of starch nanoparticles by H₂SO₄was higher than that by HCl.

A solid acid catalyst was prepared from masson pine alkali lignin in waste liquor of soda pulping by a combined process of chemical activation, carbonization, and sulfonation. The lignin-derived solid acid (LDSA) was characterized by FESEM, XRD, FTIR, TGA, XPS, BET analyses, and acid-base back titration. The carbonaceous material had high thermal stability and large specific surface area (488.4 m²/g), and the structural analyses showed that it was composed of amorphous carbon bearing -SO₃H, -COOH, and phenolic -OH groups. The lignin-derived catalyst was then applied to the hydrolysis of a microcrystalline cellulose (MCC) in aqueous system, and the yield of total reducing sugars was found to be 46.1%. It was proposed that good adsorption capacities of cellulose and desorption property of glucose on LDSA probably contributed to efficient catalytic hydrolysis.

Cetane number (CN)-a prime indicator of diesel fuel quality, is a quantity indicating the combustion behaviour of diesel fuel and compression required for ignition in diesel engines. This study examines the determination of CN of Jatropha biodiesel blends with mineral diesel using their physical properties, and their variations of CN with percentage composition of Jatropha biodiesel in the blends. Jatropha biodiesel, converted through a transesterification process of its oil, is obtained and blended with diesel to obtain blend B10 (10% biodiesel and 90% diesel) on a volumetric basis, at 25oC ambient temperature and the same basis was employed for blends B20, B30, B40 and B50. The specific gravity and mid-distillation characteristic were obtained using a hydrometer and distillation curve apparatus based on ASTM D1298 and D86 standards respectively. The CN of Jatropha oil, its biodiesel and Jatropha biodiesel blends with diesel were analytically determined, employing the empirical relationship between measured physical properties of a twovariable cetane index equation. The results show that the CN of the Jatropha biodiesel increases significantly (about 29%) after transesterification compared with that of the Jatropha oil. Moreover, the specific gravity and CN of the blends increase with the percentage composition of Jatropha biodiesel in the blends. The CN of Jatropha biodiesel is 44.10, which is 8.7% higher than that of mineral diesel (40.62). It can be implied from the research outcomes that blending Jatropha biodiesel with diesel increases the CN of the blends, thus, could be used as cetane point (number) enhancer.