The Role of Acid Concentration on Band Gap Shrinkage in Cellulose Nanocrystals Fabricated from Water Hyacinth

In this study, the fingerprint of the acid concentration during the hydrolysis process on the optical band gap of cellulose nanocrystals (CNCs) has been systematically studied. The CNCs have been prepared using hydrochloric acid at a hydrolysis temperature of 50°C and at a constant hydrolysis time of 4 hours but with varying hydrochloric cid concentrations of 5%, 10% and 15%. The crystalline structure and phase identification of the CNCs have been studied using XRD technique. UV-Vis Spectroscopy has been done and the optical band gap energy calculated by performing the Tauc’s plot. From the study, the grain size has been found to decrease with acid concentration while the band gap energy has been found to increase with increasing acid concentration. Further, the optical band gaps of the CNCs have been found to decrease with the increase in crystallite size. This shrinkage of the band gap has been attributed to the increased impurity concentration leading to the narrowing of the band gap due to the emerging of the impurity band formed by the overlapped impurity states

Hydrolysis of S. platensis Using Sulfuric Acid for Ethanol Production

S. platensis is a microalga that contains carbohydrate composition of 30.21% which makes it potential to be used as raw material for ethanol production. Hydrolysis of S. platensis is the first step for converting its carbohydrates into monosaccharides. The second step is fermentation of monosaccharides into ethanol. This research aims to study the effect of temperature and microalgae concentration on the hydrolysis of S. platensis using sulfuric acid as catalyst. This research was conducted using 300 mL sulfuric acid of 2 mol/L, hydrolysis temperatures of 70, 80 and 90 °C, and microalgae concentrations of 20, 26.7, and 33.3 g/L. The effect of temperature is significant in the hydrolysis of S. platensis using sulfuric acid. At microalgae concentration of 20 g/L and hydrolysis time of 35 minutes, the higher the temperatures (70, 80, and 90 °C), the more the glucose yields would be (8.9, 13.5, and 22.9%). This temperature effect got stronger when the hydrolysis was running for 15 minutes. Every time the hydrolysis temperature increased by 10 °C, the glucose yield increased by 13.0% at microalgae concentration of 33.3 g/L. At temperature of 90 °C and time of 35 minutes, the higher the microalgae concentrations (20, 26.7, and 33.3 g/L), the higher the glucose yields would be (25.5, 27.7, and 28.2%). The highest glucose concentration obtained was 2.82 g/L at microalgae concentration of 33.3 g/L, temperature of 90 °C, and time of 35 minutes.

Production Process of a Carbonated Drink from Red Flesh Dragon Fruit (Hylocereus polyrhizus)

The purpose of this study is to present a suitable production process of a carbonated drink from ingredients originated from red flesh dragon fruits. Additionally, optimal parameters in the hydrolysis and pasteurization stages of the juice were determined so that the product could retain the highest bioactive ingredients while still maintaining favorable color. The investigated parameters of pectinase hydrolysis process included hydrolysis temperature (35, 40, 45 and 50oC), hydrolysis time (1 hour, 2 hours, 3 hours and 4 hours), concentration pectinase enzyme level (0.4; 0.6, 0.8 and 1%) and enzyme pectinase content (0.2, 0.4, 0.6 and 0.8%). Outcomes which were considered in optimization processes included polyphenol content, vitamin C content and DPPH scavenging activity. The results are expected to aid in diversification of products from dragon fruit raw materials to meet the increasing demand of consumers.

A Novel Gelatinase from Marine Flocculibacter collagenilyticus SM1988: Characterization and Potential Application in Collagen Oligopeptide-Rich Hydrolysate Preparation

Although the S8 family in the MEROPS database contains many peptidases, only a few S8 peptidases have been applied in the preparation of bioactive oligopeptides. Bovine bone collagen is a good source for preparing collagen oligopeptides, but has been so far rarely applied in collagen peptide preparation. Here, we characterized a novel S8 gelatinase, Aa2_1884, from marine bacterium Flocculibacter collagenilyticus SM1988T, and evaluated its potential application in the preparation of collagen oligopeptides from bovine bone collagen. Aa2_1884 is a multimodular S8 peptidase with a distinct domain architecture from other reported peptidases. The recombinant Aa2_1884 over-expressed in Escherichia coli showed high activity toward gelatin and denatured collagens, but no activity toward natural collagens, indicating that Aa2_1884 is a gelatinase. To evaluate the potential of Aa2_1884 in the preparation of collagen oligopeptides from bovine bone collagen, three enzymatic hydrolysis parameters, hydrolysis temperature, hydrolysis time and enzyme-substrate ratio (E/S), were optimized by single factor experiments, and the optimal hydrolysis conditions were determined to be reaction at 60 ℃ for 3 h with an E/S of 400 U/g. Under these conditions, the hydrolysis efficiency of bovine bone collagen by Aa2_1884 reached 95.3%. The resultant hydrolysate contained 97.8% peptides, in which peptides with a molecular weight lower than 1000 Da and 500 Da accounted for 55.1% and 39.5%, respectively, indicating that the hydrolysate was rich in oligopeptides. These results indicate that Aa2_1884 likely has a promising potential application in the preparation of collagen oligopeptide-rich hydrolysate from bovine bone collagen, which may provide a feasible way for the high-value utilization of bovine bone collagen.

Hidrolisis Protein Teripang Hitam (Holothuria edulis) Menggunakan Bromelin Kasar dari Batang Nanas (Ananas comocus L)

Black sea cucumber is one type of sea cucumber whose protein content is quite high at 74-82%, not yet widely used by the community as a source of protein. One way to use it is to process the protein into a protein hydrolyzate using the bromelain enzyme which was isolated from pineapple stems. This study aims to determine the concentration of the bromelain enzyme extract and the optimum hydrolysis time to the value of the hydrolysis degree of the hydrolyzate of black sea cucumber protein. Protein hydrolysates are produced by variations of the crude bromelain concentration of 9%, 10%, 11%, and 12% (v/v) and hydrolysis time of 120, 180, 240, and 300 minutes. The results showed that the optimum degree of hydrolysis was obtained with the use of bromelain extract with a concentration of 12% with a value of 11.43% and a hydrolysis time of 240 minutes with a value of 19.17%.

Immobilization of cellulase on magnetic nanoparticles for rice bran oil extraction in a magnetic fluidized bed

This paper presents a method for extracting rice bran oil using magnetic immobilized cellulase (MIC) in a magnetic fluidized bed (MFB). Cellulase was immobilized on Fe3O4/SiO x -g-P (glycydylmethacrylate) with an average grain size of 120 nm. The rice bran was hydrolyzed using MIC combined with magnetic immobilized alkaline protease to extract rice bran oil. Under intermittent conditions, the MIC concentration was 1.6 mg/g, the liquid to material ratio was 4:1, the enzymatic hydrolysis time was 150 min, and the oil yield was as high as 85.6 ± 1.20% at 55 °C. The fluid in the MFB had a magnetic field strength of 0.022 T, a flow velocity of 0.005 m/s, and an oil extraction rate of 90.3%. This provides a theoretical basis for the extraction of rice bran oil using the subsequent MFB hydroenzyme method.

Optimization of Enzymatic Hydrolysis by Alcalase and Flavourzyme To Enhance the Antioxidant Properties of Jasmine Rice Bran Protein Hydrolysate

This study aimed to optimize the hydrolysis conditions for producing jasmine rice bran protein hydrolysate (JBH) using response surface methodology (RSM). The independent variables were the ratio of flavourzyme to alcalase (Fl: Al; 0: 100 to 15: 85; 2.84% enzyme concentration) and hydrolysis time (60–540 min). The optimum hydrolysate was obtained at an Fl: Al ratio of 9.81: 90.19 for 60 min, since it enabled high amounts of protein, high antioxidant activity and more low molecular weight proteins. The experimental values obtained were a degree of hydrolysis (DH) of 7.18%, a protein content of 41.73%, an IC50 for DPPH of 6.59 mg/mL, an IC50 for ABTS of 0.99 mg/mL, FRAP of 724.81 mmol FeSO4/100 g, and 322.35 and 479.05 mAU*s for peptides with a molecular weight of <3 and 3–5 kDa, respectively. Using a mixture of enzymes revealed the potential of mixed enzymes to produce JBH containing more small peptides and high antioxidant activity.

The advanced performance of microbial consortium for simultaneous utilization of glucose and xylose to produce lactic acid directly from dilute sulfuric acid pretreated corn stover

Background Lignocellulosic feedstocks have attracted much attention as a potential carbon source for lactic acid (LA) production because of their ready availability, sustainability, and renewability. However, there are at least two major technical challenges to producing LA from lignocellulose. Inhibitors derived from lignocellulose pretreatment have a negative impact on the growth of cells producing LA. Furthermore, pentose sugars produced from the pretreatment are difficultly utilized by most LA producers, which is known as the carbon catabolite repression (CCR) effect. This complex feedstock can be utilized by a robust microbial consortium with high bioconversion efficiency. Results In this study, a thermophilic consortium DUT50 producing LA was enriched and employed to improve corn stover (CS) utilization. Enterococcus was the dominant family in the consortium DUT50, accounting for 93.66% of the total abundance, with Lactobacillus, Bacillus, Lactococcus, and Trichococcus accounted for the remaining 2.68%. This consortium could be resistant to inhibitors concentration up to 9.74 g/L (2.88 g/L acetic acid, 2.46 g/L furfural, 2.20 g/L 5-HMF, and 2.20 g/L vanillin derived from pretreatment of CS), and simultaneously metabolizes hexose and pentose without CCR effect. Based on the promising consortium features, an efficient process of simultaneous saccharification and co-fermentation (SSCF) was developed to produce LA from acid pretreated corn stover, in which solid–liquid separation and detoxification were avoided. The key influencing factors were investigated and optimized, including dry biomass and cellulase loading, corn steep liquor powder concentration, and the pre-hydrolysis time. The highest LA titer of 71.04 g/L with a yield of 0.49 g/g-CS was achieved at a dry biomass loading of 20% (w/v), which is the highest LA production from non-detoxified acid pretreated corn stover via the SSCF process without wastewater generation reported to date. The simultaneous metabolism of hexose and pentose revealed collaboration between Enterococcus in the consortium, whereas xylose may be efficiently metabolized by Lactobacillus and Bacillus with low abundance via the pentose phosphate pathway. Conclusions The experimental results demonstrated the potential advantage of symbiosis in microbial consortia used for LA production from lignocellulosic biomass.

Optimisation of enzymatic saccharification of wheat straw pre-treated with sodium hydroxide

To enhance the reducing sugar yield in enzymatic hydrolysis, various factors (NaOH concentration, solid content and pre-treatment time) that affect the pre-treatment process were investigated and evaluated based on the reducing sugar yield of the subsequent enzymatic hydrolysis. The enzymatic hydrolysis was based on the cellulase from Trichoderma reesi ATCC 26921, the optimum NaOH pre-treatment conditions were an NaOH concentration of 1.0% (w/w), a solid content of 5.0% (w/v) and a pre-treatment time of 60 min. Various parameters that affect the enzymatic hydrolysis of wheat straw, including the solid content, enzyme loading, pH and hydrolysis time, were investigated and optimized through a Box–Behnken design and response surface methodology. The predicted optimum conditions for enzymatic hydrolysis were a solid content of 8.0% (w/v), an enzyme loading of 35 FPU/g substrate, a temperature of 50 °C, a pH of 5.3 and a hydrolysis time of 96 h. The experimental result showed that the maximum reducing sugar yield was 60.73% (53.35% higher than the wheat straw without NaOH pre-treatment), which is in accordance with the predicted conditions.

Isolation and Characterization of Nanocrystalline Cellulose Isolated from Pineapple Crown Leaf Fiber Agricultural Wastes Using Acid Hydrolysis

Pineapple crown leaf fiber (PCLF) is one of the major biomass wastes from pineapple processing plants. It consists mostly of carbohydrate polymers, such as cellulose, hemicellulose, and lignin. It can be further processed to form a more valuable and widely used nanocrystalline cellulose (NCC). This study investigates the effect of hydrolysis time on the properties of the produced NCC. The acid hydrolysis was conducted using 1 M of sulfuric acid at hydrolysis times of 1–3 h. The resulting NCCs were then characterized by their morphology, functional groups, crystallinity, thermal stability, elemental composition, and production yield. The results show that the NCC products had a rod-like particle structure and possessed a strong cellulose crystalline structure typically found in agricultural fiber-based cellulose. The highest NCC yield was obtained at 79.37% for one hour of hydrolysis. This NCC also displayed a higher decomposition temperature of 176.98 °C. The overall findings suggest that PCLF-derived NCC has attractive properties for a variety of applications.