Enzymatic hydrolysis

Background Pretreatment is a critical step in the conversion of lignocellulose to fermentable sugars. Although many pretreatment processes are currently under investigation, none of them are entirely satisfactory in regard to effectiveness, cost, or environmental impact. The use of hydrogen peroxide at pH 11.5 (alkaline hydrogen peroxide (AHP)) was shown by Gould and coworkers to be an effective pretreatment of grass stovers and other plant materials in the context of animal nutrition and ethanol production. Our earlier experiments indicated that AHP performed well when compared against two other alkaline pretreatments. Here, we explored several key parameters to test the potential of AHP for further improvement relevant to lignocellulosic ethanol production. Results The effects of biomass loading, hydrogen peroxide loading, residence time, and pH control were tested in combination with subsequent digestion with a commercial enzyme preparation, optimized mixtures of four commercial ...

Hydrolytic degradations of biodegradable poly(3-hydroxybutyrate) (PHB), polylactide (PLA) and their derivatives were explored by kinetic and structure methods at 37 and 70°C in phosphate buffer. It was revealed the kinetic profiles for copolymer PHBV (20% of 3-hydroxyvalerate) and the blend PHB-PLA (1:1 wt. ratio). The intensity of biopolymer hydrolysis depending on temperature is characterized by total weight loss and the

Hot-air (75 -100°C) pasteurisation (HAP) of birch-wood-based substrate was compared to conventional autoclaving (steam at 121 °C) with regard to shiitake growth and yield, chemical composition of heat-pretreated material and spent mushroom substrate (SMS), enzymatic digestibility of glucan in SMS, and theoretical bioethanol yield. Compared to autoclaving, HAP resulted in faster mycelial growth, earlier fructification, and higher or comparable fruit-body yield. The heat pretreatment methods did not differ regarding the fractions of carbohydrate and lignin in pretreated material and SMS, but HAP typically resulted in lower fractions of extractives. Shiitake cultivation, which reduced the mass fraction of lignin to less than half of the initial without having any major impact on the mass fraction of glucan, enhanced enzymatic hydrolysis of glucan about four-fold. The choice of heating method did not affect enzymatic digestibility. Thus, HAP could substitute autoclaving and facilitate combined shiitake mushroom and bioethanol production.

The aim of the study was to compare the production of bioethanol between banana and yam peel. Banana is one of the most popular tropical fruit consumed worldwide. Banana is a common term embracing a number of species or hybrid in the genus of the Musa of the Musacaea and cultivated mainly for its fruits. Yam is also a tuber crop in the plant genus of the Dioscorea of the Family Discoreacease that form edible tubers. The bioethanol from Banana and Yam peels were hydrolysed with Aspergillus niger for 5days, the hydroslates was fermented with Zymomonas mobilis at room temperature of 35C for 5days. The bioethanol from banana peel produced a reducing sugar of 1.047mg/ml, the concentration obtained was 0.109mg/l, the quantity of the bioethanol was 133.53g/l and the density of the bioethanol was 0.843g/ml and for Yam peel the bioethanol produced a reducing sugar of 1.253mg/ml, the concentration obtained was 0.096mg/l, the quantity of the bioethanol produced was 146.33g/l and the density of...

The effect of mild acidic and alkaline pretreatments of various plant biomasses on their enzymatic hydrolysis has been studied. The yield of reducing sugars and utilization rate of the biomass were used as reliable characteristics of enzymatic digestibility of the biomasses. The experiments showed that alkaline pretreatment was more efficient than acidic pretreatment. As a result of alkaline pretreatment, a more efficient delignification of the biomasses and considerable improvement of the digestibility parameters were observed. It was found that residual lignin content in the biomass after alkaline pretreatment was related to initial lignin content in untreated biomass. Moreover, residual lignin showed an evident negative effect on enzymatic hydrolysis of pretreated biomass samples, and its removal contributed to higher enzymatic digestibility. It is more preferred to select a mild alkaline pretreatment for biomass that has low content of initial lignin. Such treatment yielded high...

In the current work, a model for enzymatic hydrolysis and SSF has been reviewed and modified. Parameters referring to the enzymatic hydrolysis were estimated against new experimental data by using a non-linear least square regression tool in Matlab (MathWorks Inc.). To ...

Increased volume and high export value of frozen snapper products in Indonesia, can produce scrap meat that can be processed into high nutritional products. Fish protein hydrolysate (FPH) is produced from an enzymatic process using the alcalase enzyme, which contains peptides and amino acids that can be applied to other derived products. The aim of this study is to produce FPH on a scale up production, determine the characteristics of raw materials and FPH products. The method used is the enzymatic hydrolysis process, which uses alcalase enzyme at 55 C with 20.000 U/kg substrate of enzyme concentration for 7 hours. The parameters measured are the degree of hydrolysis (DH), yield, proximate analysis, and the amount of amino acids in raw materials and FPH. DH value was 71.88% ± 6.48 at the 7 hour and based on the ANOVA results the P-value < 0.05, so that the measurement at 0 7 hours shows a significantly different DH value. The yield of FPH was 89.30%, the protein content of raw ma...

The effect of mild acidic and alkaline pretreatments of various plant biomasses on their enzymatic hydrolysis has been studied. The yield of reducing sugars and utilization rate of the biomass were used as reliable characteristics of enzymatic digestibility of the biomasses. The experiments showed that alkaline pretreatment was more efficient than acidic pretreatment. As a result of alkaline pretreatment, a more efficient delignification of the biomasses and considerable improvement of the digestibility parameters were observed. It was found that residual lignin content in the biomass after alkaline pretreatment was related to initial lignin content in untreated biomass. Moreover, residual lignin showed an evident negative effect on enzymatic hydrolysis of pretreated biomass samples, and its removal contributed to higher enzymatic digestibility. It is more preferred to select a mild alkaline pretreatment for biomass that has low content of initial lignin. Such treatment yielded high...

Fiber size analysis, water retention value, and Simons' stain measurements were assessed for their potential to predict the susceptibility of a given substrate to enzymatic hydrolysis. Slight modifications were made to the fiber size analysis and water retention protocols to adapt these measurements to evaluate substrates for cellulolytic hydrolysis rather than pulps for papermaking. Lodgepole pine was pretreated by the steam and ethanol-organosolv processes under varying conditions. The Simons' stain procedure proved to be an effective method for indicating the potential ease of enzymatic hydrolysis of substrates pretreated by either process or when the pretreatment conditions were altered.

Fiber size analysis, water retention value, and Simons' stain measurements were assessed for their potential to predict the susceptibility of a given substrate to enzymatic hydrolysis. Slight modifications were made to the fiber size analysis and water retention protocols to adapt these measurements to evaluate substrates for cellulolytic hydrolysis rather than pulps for papermaking. Lodgepole pine was pretreated by the steam and ethanol-organosolv processes under varying conditions. The Simons' stain procedure proved to be an effective method for indicating the potential ease of enzymatic hydrolysis of substrates pretreated by either process or when the pretreatment conditions were altered.

Increased volume and high export value of frozen snapper products in Indonesia, can produce scrap meat that can be processed into high nutritional products. Fish protein hydrolysate (FPH) is produced from an enzymatic process using the alcalase enzyme, which contains peptides and amino acids that can be applied to other derived products. The aim of this study is to produce FPH on a scale up production, determine the characteristics of raw materials and FPH products. The method used is the enzymatic hydrolysis process, which uses alcalase enzyme at 55 C with 20.000 U/kg substrate of enzyme concentration for 7 hours. The parameters measured are the degree of hydrolysis (DH), yield, proximate analysis, and the amount of amino acids in raw materials and FPH. DH value was 71.88% ± 6.48 at the 7 hour and based on the ANOVA results the P-value < 0.05, so that the measurement at 0 7 hours shows a significantly different DH value. The yield of FPH was 89.30%, the protein content of raw ma...

This paper describes the enzymatic hydrolysis of solid residue of olive mill (OMRS) in a batch reactor with the Trichoderma reesei enzyme. Before enzymatic saccharification, crude lignocellulosic material is submitted to alkaline pre-treatment with NaOH. Optimum conditions of the pre-treatment (temperature of T=100 degrees C and OMRS-NaOH concentration ratio of about R=20) were determined. The optimum enzymatic conditions determined were as follows: pH of about 5, temperature of T=50 degrees C and enzyme to mass substrate mass ratio E/S=0.1g enzyme (g OMRS)(-1). The maximum saccharification yield obtained at optimum experimental conditions was about 50%. The experimental results agree with Lineweaver Burk's formula for low substrate concentrations. At substrate concentrations greater than 40gdm(-3), inhibitory effects were encountered. The kinetic constants obtained for the batch reactor were K(m)=0.1gdm(-3)min(-1) and V(m)=800gdm(-3).