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Biomethanation of municipal solid waste (MSW) is a slow process and the yield of biogas is usually low. The present study was carried out to examine the effect of calcium chloride (CaCl2) on anaerobic digestion of MSW. Three anaerobic digesters with different concentrations of CaCl2, namely sample without additives (Control), sample with 2.5 g/L CaCl2 (R1) and sample with 5 g/L CaCl2 (R2) were studied separately and the significant results are presented. From the experimental results, it was observed that pH decreased with an increase in the dosage of CaCl2. Total solids and volatile solids reduction percentage in digester R2 was considerably lower than Control and R1 digesters. The significant positive correlation with small increments in volatile solids and chemical oxygen demand (COD) reduction were observed with an increase in pH. The cumulative biogas production in all the three digesters (Control, R1 and R2) were observed to be 35.38, 46.46 and 37.56 L, respectively. It was also observed that the volatile fatty acids (VFAs) removal efficiency in digester R1 was the best among all the three digesters. A comparison of the effluent characteristics revealed improvement in the overall performance of the digester R1 amended with 2.5 g/L CaCl2 over the other two digesters.

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Oleaginous yeast lipids have myriad of industrial applications that are gaining significant interest owing to shorter incubation, ability to use broad spectrum substrates, and quality lipids. However, the lipid content produced is low and need to enhance by optimization of varied parameters. In the present study, crude glycerol a by-product of biodiesel industry was supplemented to Trichosporon shinodae for lipid accumulation using central composite design (CCD) of response surface methodology (RSM). The developed quadratic model was found to be significant with the R 2 value of 95.20% and adj. R 2 value of 91.97%. An optimal lipid content of 49.85 ± 0.8% (w/w) was obtained using T. shinodae with 6.2% (v/v) inoculum volume, pH 3.6, C/N ratio 105, 1.52 (g/L) of MgSO 4 , and 4.55 mM FeSO 4 in 120.72 h at 30 °C. Lipid composition from T. shinodae depicted the presence of linoleic acid (C18:2), oleic acid (C18:1), stearic acid (C18:0), palmitic acid (C18:0), myristic acid (C14:0), and lauric acids (C12:0), respectively. T. shinodae lipids have 61.1% (w/w) saturated fatty acids and unsaturated fatty acids proportion accord to 38.9% (w/w). Lipid composition of T. shinodae indicates that these lipids were suitable for synthesis of high value products like fuel additives, surfactants, detergents, and cleaning applications.

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