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[en] Two significant errors were found in this article: In Table 1, due to a missing decimal point, Dry Matter Yields are displayed ten times too high. In Figure 2, the caption of the y-axis should read kg CO2-equivalents ha−1a−1 instead of t CO2-equivalents ha−1a−1.
[en] Fish waste disposal is a major cause for concern for the seafood processing industries. Fish processing generates enormous quantities of waste as almost 45% of the live weight of fish is regarded as waste. Current ways of managing fish waste involves dumping in oceans, landfills, or treating them with already established strategies. Dumping these wastes without any form of treatment is far from being environmental friendly. Current utilization strategies suffer from disadvantages such as incomplete utilization of solid and liquid wastes or generation of new waste effluents that needs further processing. Therefore, there is a need to find an alternate/supplemental method of seafood utilization. Previously, we have reported the use of microwave hydrothermal carbonization (MHTC) to carbonize fish waste to hydrochar. Here, a conventional heating method such as a custom autoclave reactor is reported that could also be used to carbonize fish waste to hydrochar. Upon response surface design optimization, it was found that a maximal yield of hydrochar (~ 35%) can be achieved at a holding temperature of 180 °C and at a holding time of 120 min. We have also characterized the elemental, proximate, energy, and surface properties of hydrochar produced by conventional hydrothermal carbonization (CHTC). It was found that the quality of the hydrochar produced by MHTC is largely comparable to CHTC. This further proves that HTC could be employed to generate energy from non-lignocellulosic wastes such as fish waste while getting rid of the waste in an eco-friendly manner.
[en] The utilization of abundantly available lignocellulosic biomass requires an efficient cellulolytic enzyme system. Evaluation of an efficient microbial system is a crucial part for the development of useful enzyme production in an industrial process. The present study reports the production of cellulolytic enzymes from various lignocellulosic biomasses by Trichoderma harzianum strain HZN11 characterized by 18S rDNA sequencing. The organism revealed a well-balanced cellulolytic complex of enzyme production (endoglucanase 30.32 U g−1, exoglucanase 15.08 U g−1, FPase 5.56 U g−1, cellobiase 17.92 U g−1, β-glucosidase 11.21 U g−1, and xylanase 1740 U g−1) from sweet sorghum bagasse under solid-state fermentation. Statistical optimization by Plackett–Burman design constituting of 12 experimental runs at two levels of seven independent variables revealed the significant effect of four variables, namely, protease peptone, lactose, MgSO4·7H2O, and K2HPO4 on endoglucanase production at 95% confidence level with R2=97.68%. Response surface methodology using central composite design was employed with 31 experimental runs at 5 levels with 4 significant independent variables. The responses in the form of contour and 3D plots showed significant interaction effects. Significant interactions existed between the variables at p < 0.05 with R2=97.3%. The model generated through these designs was validated giving a 2.31-fold increase in endoglucanase production. The isolated T. harzianum strain HZN11 produced an efficient pool of cellulolytic enzymes which is essential for efficient hydrolysis of biomass. The strain HZN11 also possessed a significant capability of cellobiase production which is usually deficient in other strains. Higher yields of endoglucanase could be employed for bioethanol production.
[en] The investigation of processes to use oil-rich organic wastes to generate biodiesel is an important research area nowadays. In this respect, quantifying oil/fat and biodiesel with less labor demanding analytical tools such as proton nuclear magnetic resonance (1H NMR) can provide faster and more accurate acquisition of the chemical quality parameters of the organic samples. In the present study, the fat obtained from mango seed kernel (MSK) and its biodiesel were investigated using 1H NMR spectra to identify its physicochemical parameters. The results indicate that MSK fat shows high oxidative stability, and the biodiesel produced from MSK fat was compatible with European (EN 14214) and Brazilian (RANP 07/08) standards. The 1H NMR technique was efficient for providing the chemical parameters of MSK fat and its biodiesel without the need of any pretreatment. In addition, complementary analysis was performed to determine the MSK biodiesel quality.
[en] In the present study, we synthesized cost-effective biocatalysts by immobilizing lipase on different low-cost matrixes. The oil obtained from Pinnai (Calophyllum inophyllum) seed, a non-edible feedstock, was used for biodiesel production. The reaction was catalyzed by immobilized lipase. It was found that lipase immobilized on silica aerogel provided highest percentage yield of fatty acid methyl ester (FAME) compared to other matrixes. The most significant finding of the research was that the lipase immobilized on silica aerogel showed negligible reduction in FAME yields even after 8 cycles of reuse, thus providing a real, cost-effective option for biodiesel production. .
[en] Rice straw and rice husks occur in large quantities as side streams of the world wide rice production. These side streams can be used as a renewable source of energy via the biochemical as well as the thermochemical conversion route. Exemplarily for samples from various South-East Asian countries, the most important characterizing figures are measured analytically. Then, the two conversion routes—based on a thermochemical as well as on a biochemical conversion—are discussed in detail. Based on such technological solutions as well as the measured data, nine case studies for each conversion system are defined and assessed related to the levelized costs of electricity (LCOEl) and energy (LCOEn). Additionally, the specific substrate demands (SSDs) and specific land demands (SLDs) are calculated indicating the mass and area efficiency of chosen substrates and systems.
[en] The production of bioethanol from lignocellulosic feedstock has proven to be a complex task due to the recalcitrant structure of the biomass. Organosolv pretreatment is a promising alternative to remove nearly pure lignin from the biomass and make the sugars available for conversion. However, in order for the organosolv pretreatment to be technically feasible, an efficient solvent recycle is required. This work studied the complete process for lignocellulosic bioethanol production based on organosolv pretreatment method. First, process synthesis is applied to devise six process alternatives for the bioethanol production based on theoretical and experimental works. The analysis was focused on the solvent recovery and recirculation, integrating the pretreatment and product separation and purification areas. Technical and economic indicators were employed to reveal the best alternative among the proposed designs. The results showed that the minimum ethanol selling price for the process was US$1.27/kg of ethanol with a total energy consumption of 29.02 kWh per kilogram of ethanol produced, with 43% of that from hot utilities and 57% from cold utilities.
[en] Dilute acid hydrolysis is typically conducted on wood to hydrolyze cellulose and hemicellulose into their compositional sugars, furfurals, or organic acids. However, lignin obtained in this process, also called hydrolysis lignin, cannot be generally used as a functional material. To overcome uncontrolled self-condensation of lignin, wood meal was impregnated with a small amount of p-cresol, and then, acid hydrolysis was performed with 1.1% sulfuric acid at 180 °C for 60 min. The cresol hardly changed the main products in the hydrolysate: glucose, formic acid, and levulinic acid. Much larger amount of lignin was extracted from the hydrolysis residue with tetrahydrofuran or by soda cooking than in the process without p-cresol impregnation. It seemed that the impregnated p-cresol was covalently bonded to lignin during acid hydrolysis and successfully prevented the self-condensation of lignin molecules, contributing improvement of the solubility of the resultant lignin in organic solvents or aqueous sodium hydroxide. Our hydrolysis process balances the valorization of carbohydrate with that of lignin.