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Abstract Pretreatment of the empty fruit brunch (EFB) from oil palm was investigated for H 2 fermentation. The EFB was hydrolyzed at various temperatures, H 2 SO 4 concentrations, and reaction times. Subsequently, the acid-hydrolysate underwent enzymatic saccharification under various temperature, pH, and enzymatic loading conditions. Response surface methodology derived the optimum sugar concentration (SC), hydrogen production rate (HPR), and hydrogen yield (HY) as 28.30 g L−1, 2601.24 mL H 2 L−1d−1, and 275.75 mL H 2 g−1 total sugar (TS), respectively, at 120 °C, 60 min of reaction, and 6 vol% H 2 SO 4 , with the combined severity factor of 1.75. Enzymatic hydrolysis enhanced the SC, HY, and HPR to 34.52 g L−1, 283.91 mL H 2 g−1 TS, and 3266.86 mL H 2 L−1d−1, respectively, at 45 °C, pH 5.0, and 1.17 mg enzyme mL−1. Dilute acid hydrolysis would be a viable pretreatment for biohydrogen production from EFB. Subsequent enzymatic hydrolysis can be performed if enhanced HPR is required. Highlights • Dilute acid and enzymatic hydrolysis were optimized for oil palm empty fruit bunch. • Response surface methodology was used for optimization of pretreatment. • Dilute acid hydrolysis effectively pretreated the biomass for H 2 fermentation. • Subsequent enzymatic saccharification enhanced H 2 production rate. [ABSTRACT FROM AUTHOR]

The native form of lignocellulosic biomass is resistant to enzymatic breakdown. A well-designed pretreatment that can promote enzymatic hydrolysis of biomass with reasonable processing cost is therefore necessary. To this end, a number of different types of pretreatment technologies have been developed with a common goal of making biomass more susceptible to enzymatic saccharification. Among those, a pretreatment method using alkaline reagent has emerged as one of the most viable process options due primarily to its strong pretreatment effect and relatively simple process scheme. The main features of alkaline pretreatment are that it selectively removes lignin without degrading carbohydrates, and increases porosity and surface area, thereby enhancing enzymatic hydrolysis. In this review, the leading alkaline pretreatment technologies are described and their features and comparative performances are discussed from a process viewpoint. Attempts were also made to give insights into the chemical and physical changes of biomass brought about by pretreatment. [ABSTRACT FROM AUTHOR]

Abstract: The efficacy of extrusion pretreatment was evaluated by enzymatic hydrolysis and simultaneous saccharification and fermentation (SSF) with straw of rapeseed, Brassica napus, an agricultural residue. An acceptable pretreatment result was obtained at a barrel temperature of 165 °C, acid concentration of 20 g L−1, liquid feeding rate of 13.4 cm3 min−1, solid feeding rate of 1.0 g min−1, screw rotation speed of 6.3 rad s−1, and residence time of 10.2 min, with a yield of xmg, representing the sum of the corresponding hydrolyzed sugars; xylose, mannose and galactose, of 794.3 g kg−1 and a glucose release of 21.0 g kg−1. These were calculated to be 963.0 g kg−1 and 910.3 g kg−1 based on cellulose and hemicellulose recoveries,respectively. The highest enzymatic digestibility of 781.0 g kg−1was higher than that obtained from the batch pretreatment with dilute acid by 1.4-fold. The SSF process afforded an ethanol concentration of 16.0 g L−1, corresponding to an ethanol yield of 790 g kg−1 based on the total available cellulose in the pretreated rapeseed straw. [Copyright &y& Elsevier]

Agricultural residues are a potentially economical and eco-friendly source for second-generation ethanol production. In the present study, efficient cellulolytic enzyme production was studied using agricultural residues as a carbon source. Four types of agricultural residues were evaluated as carbon sources for Trichoderma harzianum KUC1716. Barley straw was identified as the optimal carbon source for the fungus such that the highest enzyme activity occurred in these cultures compared to cultures that used empty fruit bunches (EFB), miscanthus, or rice straw sources. T. harzianum KUC1716 produced high levels of filter paperase (FPase) and cellobiohydrolase (CBH) under optimized medium conditions when a central composite design and response surface methodology were used. Furthermore, T. harzianum KUC1716 fungal enzymes exhibited a significant hydrolysis yield for various types of agricultural residues compared to a commercial enzyme. Our study demonstrates that utilization of agricultural residues for both enzyme production and enzymatic saccharification will contribute to an increase in economical and eco-friendly production of biofuels and bio-based products. [ABSTRACT FROM AUTHOR]

Abstract: The study of bioproduct production, such as bioethanol and biochemicals, from inexpensive biomass has recently attracted considerable attention. Compared to land biomass, marine biomass can be grown rapidly and is easily cultivated without the need for expensive equipment. In addition, annual CO2 absorption by marine biomass is five to seven times higher than that of wood-biomass and the carbohydrate content is higher and can easily be converted to chemicals through proper chemical processes. In the production of various biochemicals from marine biomass, levulinic acid is a highly versatile chemical with numerous industrial uses and the potential to become a commodity chemical. It can be used as a raw material for resins, plasticizers, textiles, animal feed, coatings and antifreeze. The present study was carried out to determine the optimum conditions of temperature, acid concentration and reaction time for levulinic acid production from marine biomass Gelidium amansii using two-step treatment. In the first hydrolysis step, solid-state cellulose was obtained through acid soaking and used to produce ethanol by fermentation and liquid-state galactose. In the second hydrolysis step, the liquid-state galactose was converted into levulinic acid via a high-temperature reaction in a batch reactor. The overall production conversion of G. amansii biomass to levulinic acid in the two-step acid hydrolysis was approximately 20.6%. [Copyright &y& Elsevier]