Higher Digestibility Research Articles

Ultrasound‐assisted alkaline extraction of proteins in several algae and their nutritional characteristics

SummaryUltrasound‐assisted alkaline extraction (UAAE) and the nutritional quality of proteins from five algae (Arthrospira platensis, Cladophora glomerata, Porphyra tenera, Laminaria japonica and Undaria pinnatifida) were investigated. The UAAE of the A. platensis protein using a 60% amplitude level and 30 min extraction time provided the highest protein yield (81.86%) and altered the surface of A. platensis. Amino acid profiles revealed that lysine and branched‐chain amino acids (BCAAs) were dominant in most algal proteins. The C. glomerata protein had the highest digestibility (94.09%) and protein digestibility‐corrected amino acid scores for the BCAAs. The L. japonica protein demonstrated a rich source of aspartic and glutamic acids, giving an umami taste. The algal proteins contained low contents of carbohydrates (3.87–44.83 mg glucose equivalents g−1) and nucleic acids (0.60–8.57 mg g−1), while total phenolics were 6.13–70.13 mg gallic acid equivalents g−1. Algal proteins could be a good ingredient in developing vegan and vegetarian foods.

Multicriteria optimal design of emamectin benzoate microparticles obtained by spray drying and ionic gelation

Emamectin benzoate (EB) is an antiparasitic used to control Caligus rogercresseyi in Chile. However, it has lost efficacy, and the parasite has been exposed to a sublethal dose. Microencapsulation has been suggested as an alternative method to protect and control the release of poorly absorbed drugs to ensure their lethal doses. Accordingly, design of experiments (DOE) and response surface methodology (RSM) were applied to find optimal conditions for EB's ionic gelation (IG) and spray drying (SD) microencapsulation. We used multiobjective (MOO) and multi-response optimization techniques as the desirability function (DFA) to obtain optimal conditions that produce microparticles that satisfy several criteria, such as low gastric digestion (GD) and high yield (Y), encapsulation efficiency (EE), load capacity (LC), and intestinal digestion (ID). The optimization process prioritized the digestion responses and was constrained according to a mass balance. MOO generated theoretical solutions that were better than any of the DOE experimental solutions. Both optimization methods achieved a more balanced performance than the responses obtained in the experimental design. Each optimization method produced better experimental responses than the other in some responses. In SD, DFA yielded higher LC, GD, and ID than MOO by 7.5%, 9.3%, and 2.1%, respectively. In contrast, MOO obtained higher Y and EE than DFA by 6.2% and 10.1%, respectively. In IG, the DFA method yielded a solution with better responses than MOO in LC (3.7%), GD (7.4%), and ID (3.2%), while the MOO solution was better in Y (14.2%) and EE (19.3%). Both multicriteria optimization techniques were suitable for obtaining optimal solutions; however, neither proved superior in all cases.

Anti-Nutritional Factors and Protein Dispersibility Index as Principal Quality Indicators for Soybean Meal in Diet of Nile Tilapia (Oreochromis niloticus GIFT), a Meta-Analysis.

Simple SummarySoybean meal is an effective protein source in aquafeeds and is characterized by high protein content, high digestibility, reasonable price, and stable supply. The quality of soybean meal varies with factors such as seed genotype, soil type, planting area, processing conditions, storage conditions, etc. Differences in soybean meal quality may lead to differences in the production performances of animals. For this reason, we investigated the nutrient composition, anti-nutritional factors and physicochemical properties of different soybean meals produced on the same production line with soybeans from different origins, and compared the effects of different soybean meals on the physiological characteristics of Nile tilapia (Oreochromis niloticus GIFT). This study identified key indicators that could distinguish the quality of soybean meals, and established a correlation model between quality indicators of soybean meal and the growth performance of Nile tilapia. These results are of great significance for evaluating the quality of soybean meals and promoting the efficient application of soybean meal in aquafeeds.Soybean meal (SBM) is the most important plant protein source in animal feed. This study investigated the characteristics of different SBMs, produced by soybeans from America and Brazil (SBM-A and SBM-B) in 2017–2021 under the same controlled conditions. The effects of different SBMs on the growth performance of Nile tilapia (Oreochromis niloticus, GIFT) and apparent digestibility coefficients (ADCs) of nutrients and energy were studied. The results showed that protein dispersibility index (PDI), urease activity (UA), glycinin and fiber were the four primary key indicators for distinguishing the characteristics of the tested SBMs. The meta-analysis results suggested that UA, glycinin, and fiber showed a negative effect on the survival rate (SR) and weight gain rate (WGR) of the Nile tilapia, whereas β-conglycinin, PDI, and nitrogen solubility index (NSI) had a positive effect on the SR and WGR of the fish. The ADCs of dry matter, the gross energy, phosphorus, crude protein, valine (Val), lysine (Lys), histidine (His), serine (Ser), and glutamate (Glu) of the Diet-A group (SBM-A inclusion) were significantly higher than those in the Diet-B group (SBM-B inclusion) (p < 0.05). However, no significant difference was found in ADCs of macro-nutrients between the two SBMs (p > 0.05). Overall, PDI, UA, glycinin, and fiber were the main indicators reflecting the characteristics of the tested SBMs, and UA, glycinin, β-conglycinin, and PDI had the greatest impact on the growth performance of Nile tilapia in this study. PDI was a more sensitive indicator than NSI for representing the protein quality of SBM.

Connecting nutritional facts with the traditional ranking of ethnobotanically used fodder grasses by local farmers in Central Punjab of Pakistan

The local farmers of Central Punjab, Pakistan have been using indigenous grasses as vital components of ruminant diets, but little is reported about their nutritional potential. Hence this study investigated nutritive potential of a selection of ethnobotanically important fodder grasses. Multiple nutritional parameters (proximate components, fibre fractions), secondary metabolites (phenolics, tannins) and in vitro digestibility values were determined. Furthermore, the legitimacy of ethnobotanical knowledge of local inhabitants about these grasses was also verified. The results suggested that majority (77%) of these grasses can be regarded as good quality fodders because of their high protein (169 g/kg) and good digestibility (457 g/kg) with moderate fibre (≤ 602 g/kg), lignin (≤ 50 g/kg) and secondary metabolites (total phenols ≤ 87 g/kg, total tannins ≤ 78 g/kg, condensed tannins ≤ 61 g/kg). Pearson correlation between nutritional parameters indicated that in vitro digestibility values were positively correlated with crude proteins (IVDMD, r = + 0.83 and IVOMD, r = + 0.83 respectively) and negatively correlated with fibre (NDF, r = − 0.91), ADF, r = − 0.84 and ADL, r = − 0.82) contents. Moreover, a positive relationship was identified between ethnobotanical knowledge and laboratory findings for studied grasses. Spearman correlation test showed that ranking of grasses based on ethnobotanical preferences were highly correlated (r values) with the laboratory results for CP (0.85), NDF (− 0.76), ADF (− 0.72) and ADL (− 0.62). The resilient complementarities between ethnobotanical preferences and nutritive analysis authenticate farmer’s traditional knowledge, which needed to be aligned with the corresponding scientific data. Farmers can use these findings for appropriate fodder selection and development of precise supplements for feeding ruminants within a sustainable and economically viable livestock industry for food security.

Storage and Packaging Effects on the Protein Oxidative Stability, Functional and Digestion Characteristics of Yak Rumen Smooth Muscle.

The objective of this study was to investigate the effects on protein oxidative stability, functional and digestion characteristics of yak rumen smooth muscle with overwrap packaging using oxygen-permeable film (OWP) and vacuum packaging bag (VP) during storage (0, 7, 14, 28, 42, 56, 84, 168 and 364 days) at −18 °C. The results show that yak rumen smooth muscle was oxidized with frozen storage through the formation of protein carbonyls and disulfide bonds, the loss of total sulfhydryl. The emulsifying activity of yak rumen smooth muscle protein (SMP) under VP began to perform a higher level than that under OWP after 14 days, and the foaming capacity under VP showed the highest level on the 28th day of 111.23%. The turbidity under VP reached the minimum 0.356 on the 28th day as well, followed by significantly increasing on the 56th day compared with OWP. The digestibility of yak rumen SMP under both OWP and VP reached the maximum on the 28th day of frozen storage. Moreover, yak rumen under VP at 28–56 days of frozen storage had good functional properties and high digestibility of SMP, which showed better edible value.

Environmental assessment of a two-stage high pressure anaerobic digestion process and biological upgrading as alternative processes for biomethane production

Biomethane plays a key role in achieving decarbonization and sustainable development goals. According to the objectives that arise, choosing the most suitable production system allows optimization of production, thereby reducing CO2 emissions. In this study, three biomethane production scenario life cycle assessments were compared to determine which would maintain the lowest CO2 emissions. Conventional anaerobic digestion and an innovative process called two-stage high pressure anaerobic digestion were considered. These methods were combined with two upgrading processes: water scrubbing and biological upgrading. Cattle manure and sugar beets were used as substrates for the process. Emissions were 805.6 gCO2eq/m3CH4 for the traditional biogas production process combined with water scrubbing and 450.3 gCO2eq/m3CH4 for the two-stage anaerobic digestion process combined with biological upgrading. Furthermore, the analysis demonstrated that these values would be reduced by 29.5 % and 48.0 % if electrical energy were produced using only renewable energy sources.

Mixing of flour mixture components in the production of pasta from nontraditional raw materials

Along with a balanced amino acid composition and high protein digestibility, food products should contain complex carbohydrates and ballast substances (dietary fibers) that ensure the normal functioning of the digestive organs. In this regard, fresh raw foods for dietary pasta are of interest for modern pasta production. It is to such raw materials for the manufacture of dough that flour and starch from some cereals, triticale flour, and stale deformed bread are referred. When forming pasta dough from nontraditional flour raw materials, an important technological value for giving the best rheological properties of the dough is the uniform distribution of the binder component in the mixture – dry wheat gluten (DWG). As an object of experimental research to study the mixing process, a loose flour mixture of cereals (barley, oats, corn, buckwheat, millet, peas, and soybeans) was used, compiled based on calculating the recipe using computer programs. The prepared mixtures are a valuable source of nutrients and minerals. At the same time, to improve the technological properties of the dough as a biologically active additive, 25% DWG is introduced to improve the rheological properties of the dough.

A novel approach based on enzymatic hydrolysis for the valorisation of edible Parmigiano Reggiano cheese rinds

The growing market for shredded cheeses (such as flakes, internal cylinders, snacks and portions without rind) generates a large amount of Parmigiano Reggiano (PRRE) rind by-products. With the aim to provide a valorisation route for edible PRRE rinds, enzymatic hydrolysis methods were performed to produce a protein hydrolysate starting from the rinds at two ripening stages (12 and 24 months), which were previously characterised for their proximate composition. The results showed that, compared with the inner, the rind section has significantly higher protein (42.4% versus 29.7%) and lipid percentages (36.6% versus 29.7%), due to the lower moisture content (15.7% versus 32.4%). Then, after a single step of enzymatic hydrolysis, high-quality high-protein ingredients with low lipid amount (10–20%) and high digestibility (especially for the high amount of free amino acids at about 50 g 100 g−1 cheese) were obtained, to be potentially used in different food applications.

Kajian daya cerna pati cookies kecambah sorgum (Sorghum bicolor [L.] Moench) dengan tersubstitusi tepung kacang tunggak (Vigna unguiculata L.)

The high use of wheat flour today makes Indonesia dependent on wheat imports. One of the commodities that can replace wheat is sorghum (Sorghum bicolor [L.] Moench), this is confirmed by various studies. The purpose of this study was to determine the balance of sorghum flour and cowpea flour as raw materials for making cookies which have high starch digestibility characteristics. This study used a Randomized Block Design (RAK) method which consisted of six treatments and three replications. The treatments were the proportions of sorghum flour and cowpea flour of 90:10, 80:20, 70:30 and the proportions of sorghum sprouts flour and cowpea flour were 90:10, 80:20, 70:30. The results showed that cookies with sorghum sprouts flour and cowpea flour 90:10 were the best treatment with 23.35% starch digestibility.&#x0D; &#x0D; Keywords: Cookies, Sorghum, Starch Digestibility.

Exogenous enzymes in sheep diet: nutritional and physiological parameters

The objective of this study was to evaluate the effect of adding exogenous enzymes to the diet on nutrient intake and digestibility, nitrogen balance, ingestive behavior and rumen movement of ewe lambs. Five ewe lambs, Dorper x Santa Inês crossbred, with an average age of 7 ± 1 months, average weight of 36.40 ± 2.36 kg were assigned in a 5x5 Latin square design. The treatments consisted of adding exogenous enzymes to the concentrate: Allzyme, Fibrozyme®, Amaize®, Mix and Control. Analyses of variance were applied and means were compared by the SNK test, and non-parametric Kruskal Wallis test at 5% significance. The dry matter intake in relation to body weight, crude protein intake and nitrogen intake were higher with the use of amylolytic enzyme compared to the other treatments (p &lt;0.05). Nitrogen balance was higher with the use of amylolytic enzymes and the Allzyme® enzyme complex (p &lt;0.05). A longer time spent in total chewing was observed with the inclusion of fibrolytic and amylolytic enzymes without changes in rumen movement. The use of exogenous enzymes promotes better use of nutrients, with high digestibility of dry matter, neutral detergent fiber and crude protein.

Stabilization of the quality of animal feed premixes during storage by introducing special additives

Studies of additives (copper chelate, pure culture of microorganisms micromycetes Trichoderma harzianum F114, enzyme preparation of b-mannanase) were carried out. Chelated compound of the trace element copper, its physical and mechanical properties, namely humidity, angle of repose, bulk density, hygroscopic point, average particle size were considered. The technique of cultivation of the microscopic fungus Trichoderma harzianum F114 is presented. The determination of the physical and mechanical properties of the enzyme preparation of b-mannanase (humidity, angle of repose, degrees, bulk density, average particle size, conditional caking) has been shown in the work. For the experiments, we used arbitration methods for assessing the quality of research objects. The components of the premixes should be stable during storage, should not have a pronounced aggressive effect on other biologically active substances, should be evenly distributed in the mass of the finished product, and have a high digestibility for the animal's body. It has been established that the introduction of the studied ingredients into the composition of the premix formulation will not have a negative effect on the quality of the premixes and compound feed.

Preparation of Functional Pasta Supplemented with Amaranth Pregelatinized Extruded Flour

Semolina pasta with improved nutritional properties is increasingly demanded by consumers. High protein content and low starch digestibility are features desired for a functional pasta. In this work, amaranth flour was used for 50% supplementation of semolina in pasta preparation. Raw amaranth flour increased protein from 11.7 g/100 g to about 14.0 g/100, dietary fiber from 6.8 g/100 g to about 8.0–10.0 g/100 g. However, raw amaranth flour deteriorated the texture of cooked pasta by increasing hardness from 15.7 to 52.8 N and reducing cohesiveness from 0.71 to 0.55. Pregelatinizations at 50 and 100% were explored to reduce the adverse effects of raw amaranth flour. The gelatinized amaranth flour mimicked the texture of semolina pasta, although cooking loss increased from 3.3 g/100 g to about 9.2 g/100 g, and the water absorption showed a marked reduction from 116.4% to about 80.0–84.0%. The in vitro starch digestibility was similar for pasta made with semolina and pasta containing pregelatinized starch, although digestibility decreased from 95 to 85% for raw amaranth flour. Overall, the results showed that amaranth flour offered advantages and drawbacks for the formulation of pasta with improved nutritional features.

Brown shrimp (Crangon crangon) processing remains as ingredient for Litopenaeus vannamei feeds: Biochemical characterisation and digestibility

Processing remains of brown shrimp, Crangon crangon, account for up to 60 % of the catch while only the small muscle fraction is used for human consumption. Incorporation into aquafeeds for high-valued species would reduce waste, create by-product value and promote sustainable aquaculture development. A detailed chemical characterisation of the remains from mechanically peeled brown shrimp was made and apparent nutrient digestibility coefficients in Litopenaeus vannamei were investigated. Brown shrimp processing remains (BSPR) contain substantial amounts of key nutrients (521 g⋅kg-1 crude protein, 74 g⋅kg-1 total lipid, 15 MJ⋅kg-1 gross energy) and valuable functional ingredients were detected (cholesterol, astaxanthin). Apparent energy (82 %) and protein (86 %) digestibility coefficients reveal good bioavailability of these nutrients. Dry matter digestibility was lower (64 %) presumably due to the high ash content (244 g⋅kg-1). The amino acid profile meets dietary requirements of penaeid shrimp with high apparent lysine and methionine digestibility coefficients. Analysis of macro- and micro minerals showed reasonable levels of required dietary minerals (phosphorus, magnesium, copper, manganese, selenium, zinc) and apparent copper digestibility was high (93 %). Contamination levels present in BSPR were below European standards acceptable for human consumption. Processing remains of brown shrimp have a high potential as alternative feed ingredient in sustainable diets for L. vannamei in recirculating aquaculture systems.

Cooking, Sensory Properties, Curcumin Retention, and In vitro Digestibility of Rice as Affected by Polishing and Turmeric Concentration

AbstractThe high digestibility of cooked rice causes an abrupt increase in blood sugar levels. Therefore, efforts are being made to find out means of lowering the digestibility of cooked rice. In the present study, brown and polished variants of four Kashmiri rice cultivars (SR‐4, K‐39, Mushq Budij, and Pigmented) are cooked with turmeric powder at varying concentrations (0, 1, and 2% w/w, rice basis) using the excess water method. The prepared rice is evaluated for cooking, sensory properties, curcumin retention, and in‐vitro digestibility to understand the effect of polishing and turmeric concentration on various properties. The addition of turmeric to rice leads to significant improvement in minimum cooking time and cooked length breadth ratios of samples irrespective of polishing. However, gruel solids loss in cooked rice decreases significantly (p ≤ 0.05) with the addition of turmeric powder. The best overall acceptability score of cooked rice samples is observed after the addition of turmeric at 1% concentration. With an increase in the amount of turmeric addition an increase in RS contents of cooked rice is observed. Therefore, rice cooked with turmeric powder can be considered as functional food for the diabetic population.

Profiling the Diversity of Sweet Pepper ‘Peperone Cornetto di Pontecorvo’ PDO (Capsicum annuum) through Multi-Phenomic Approaches and Sequencing-Based Genotyping

The sweet pepper (Capsicum annuum) ‘Peperone Cornetto di Pontecorvo’ is a prominent local variety at risk of genetic erosion cultivated in the Latium region (Italy). This horn-shaped landrace is recognized for its high digestibility due to the thinness of the skin and has been granted the Protected Designation of Origin (PDO) mark since 2010. Nowadays, different accessions are claimed as ‘Peperone Cornetto di Pontecorvo’ and no assay has been conducted to determine authenticity. In this study, 14 ‘Peperone Cornetto di Pontecorvo’ accessions and 7 similar horn-type peppers were investigated for their morpho-agronomic performance and chemical composition. Digital fruit imaging was implemented as a tool to pinpoint with high accuracy the morphometric parameters of berries. In total, 52 traits were scored. The multivariate analysis revealed different clusters that separated ‘Peperone Cornetto di Pontecorvo’ from similar types. The weight and size of fruits, as well as the content of soluble solids, were the most discriminating factors among the cultivars studied. Genomic fingerprinting was performed using ddRAD sequencing, yielding a total of a total of 120 million raw sequences and 2196 high-quality SNPs. Both Bayesian and hierarchical clustering analyses confirmed the existence of two different (K = 2) sub-populations separating ‘Peperone Cornetto di Pontecorvo’ accessions from similar types, thus highlighting a high membership (qi &gt; 0.97) coefficient for accessions cultivated in the Pontecorvo area (Frosinone district). In addition, a direct relationship was found between the genetic diversity of cultivars and their geographical provenance, providing hints on the breeding history of local varieties in diverse rural areas. Genomic markers are revealed as a valuable tool to establish the uniqueness and distinctness of this local variety. This information will be very helpful for recovery, enhancement, and protection from possible imitations.

Insects as Feed for Companion and Exotic Pets: A Current Trend.

Simple SummaryCurrently, there is a wide variety of insect-based pet foods and treats; however, there are several questions about the nutritional contribution of insects for dogs and cats, their health effects, safety aspects and the legal framework for their use as ingredients or feed. The insect-based ingredients used are mainly meal and fat from black soldier fly larvae, mealworm larvae and adult house crickets. There are few studies on the use of insects as food ingredients for pets, and most of them have studied some aspects in dogs. It has been said that they do not affect health, are well accepted and tolerated, do not alter the microbiota and could have the potential to be used as hypoallergenic ingredients. Insects provide a high nutritional value, with a high content of protein and amino acids with good digestibility for dogs. In cats, there is scarce information and more studies are needed. In exotic pets, their use is generalized. Dog owners are willing to use insects as ingredients, but in processed formats such as meal or as part of food or treats. Future research should focus on safety issues and effects on the health, nutrition and feeding behavior of traditional pets, such as dogs and cats.The objective of this review was to carry out a comprehensive investigation of the benefits of incorporating insects as a pet food ingredient and the implications this can have in determining a market demand for insect-based pet foods. Black soldier fly larvae (Hermetia illucens), mealworm larvae (Tenebrio molitor) and adult house crickets (Acheta domesticus) are currently used in pet food. These insects are widely fed to exotic pets, mainly in whole, live or dehydrated formats. They are also incorporated as meal or fat and are offered to cats and dogs as dry or wet food and treats. Scientific studies about the use of insects for dog and cat feed are scarce. Most studies are in dogs. Research shows that insect nutrients, mainly amino acids, have high digestibility, are beneficial to health, do not have any detrimental effect on the gut microbiota and are accepted by dogs. In several countries, insects are approved for use in pet food and commercialization has spread throughout the world. Pet owners are willing to try foods made with insect meal for their pets. In conclusion, the use of insects in pet food is a reality that is taking on more and more prominence.

Extraction of biodegradable microplastics from tissues of aquatic organisms

Biodegradable plastics (BPs) have been given high hopes to substitute conventional plastics, but their biodegradation requires strict conditions. BPs can accumulate for a long time in the environment and even derive biodegradable microplastics (BMPs), thus threatening wildlife and ecosystems. However, no efficient method is available for extracting BMPs from organisms' tissues. This study used multi-criteria decision-making (MCDM) methods to comprehensively evaluate and optimize extraction protocols of five BMPs from economic aquatic species. Digestion time, digestion efficiency, mass loss, cost, polymer integrity and size change were selected as evaluating indictors. According to the screening results of MCDM methods, Pepsin+H2O2 was selected as the optimal digestion method of BMPs because of its highest comprehensive score, which has high digestion efficiency (99.56%) and minimum plastic damage. Compared with olive oil, NaI is more suitable for separating BMPs from the digested residues. Furthermore, the combination of Pepsin+H2O2 digestion and NaI density separation was used to extract all five kinds of BMPs from the bivalve, crab, squid, and crayfish tissues, and all the recovery rates exceeded 80%. These results suggest that the optimal protocol is practicable to extract various BMPs from various aquatic organisms.

Intraspecific interactions at high predator densities affect the predation efficiency ofNeoseiulus californicus(Acari: Phytoseiidae) when prey density is low

AbstractQuantifying functional responses is a cornerstone in evaluating the predation efficiency of biological control agents such as predatory insects and mites. In this study, we investigate whether the efficiency ofNeoseiulus californicus(Acari: Phytoseiidae) in consuming prey is driven by intraspecific interactions. For this purpose, laboratory functional response experiments were conducted using one, two, three or four predators at several initial egg densities of the two‐spotted spider mite,Tetranychus urticae(Acari: Tetranychidae).The data fitted to the predator‐dependent Crowley–Martin model which accounts for intraspecific interactions. The results suggest that at high prey densities, i.e. the densities at which the predator is satiated, intraspecific interactions did not affect the predation potential ofN.californicus, as the maximum number ofT. urticaeeggs that can be attacked by predator individuals did not differ between treatments (i.e., predator densities).However, at low prey densities and the highest predator density (i.e., four individuals), intraspecific interactions were detected, as revealed by the estimated attack rates, i.e. the per capita prey consumption at low prey densities. While mean attack rates did not differ significantly when one, two and three predators were exposed to prey, when predator density increased to four individuals, attack rate was considerable lower compared to the other predator densities.These results indicate that intraspecific interactions are more intense at low prey densities, where the predator is not satiated and therefore digestion breaks do not exist. In contrast, at high prey densities digestion breaks exist, so that may fully accommodate the cost of intraspecific interactions. These results also suggest that predator density should be considered when functional responses are measured.

Immobilized exoglycosidase matrix mediated solid phase glycan sequencing

Full characterization of the attached carbohydrate moieties of glycoproteins is of high importance for both the rapidly growing biopharmaceutical industry and the biomedical field. In this paper we report the design and production of three important 6HIS-tagged exoglycosidases (neuraminidase, β-galactosidase and hexosaminidase) to support rapid solid phase N-glycan sequencing with high robustness using immobilized enzymes. The exoglycosidases were generated in bacterial expression systems with high yield. Oriented immobilization via the 6HIS-tag portion of the molecules supported easy accessibility to the active sites and consequently high digestion performance. The three exoglycosidases were premixed in an appropriate matrix format and processed in a low-salt buffer to support long term storage. The digestion efficiencies of the immobilized enzymes were demonstrated by using solid phase sequencing in conjunction with capillary electrophoresis analysis of the products on a commercial glycoprotein therapeutic (palivizumab) and human serum derived fluorophore labeled glycans.

Synergetic effects of biochar addition on mesophilic and high total solids anaerobic digestion of chicken manure

High solids anaerobic digestion (AD) of chicken manure (CM) is often challenging due to ammonia-N inhibition and accumulation of volatile fatty acids (VFAs). This study evaluated the effect of adding biochars from different feedstock to ameliorate semi-dry AD of fresh CM during batch fermentation. Experiments were performed in 300 mL at two total solid (TS) levels (12% and 15%) under mesophilic (36 ±1ᵒC) conditions for 55 d, using activated sludge as inoculum. Treatments included: fresh CM (at 12% or 15% TS) mixed separately with rice husks char (RB), wood char (WB) and bamboo char (BB) at biochar dosages of 2.5%, 5% and 10% of TS in the CM, inoculum only and inoculum plus CM without addition of char as the control. Results indicated that addition of biochar reduced the lag phases to 4–5.4 d and AD performances were significantly improved with total volatile solids removal of 53–67% and 62–71%, and cumulative methane of 277–380 mL/gVS (CH4 content ≈ 51–63%) and 297–438 mL/gVS (CH4 content ≈ 49–67%) at 12% and 15% TS, respectively. Biochar buffered over acidification and stabilized pH in the range of 6.5–7.8 but mild ammonia inhibition still occurred in all biochar treatments due to the high residual total ammonia-N (4.3 g–5.6 g/L). For all the investigated parameters, WB amended digesters exhibited the best results owing to its high specific surface area, porosity, cationic exchange capacity, and elemental composition which were superior to those of RB and BB. At 10% dosage of all tested biochars, the AD process was more stable and methane content neared optimal of >65% CH4. Therefore, addition of biochar from lignocellulosic materials at a given threshold dosage could promote semi-dry and dry biogas production from chicken manure and thus add value to this waste which in most cases is improperly managed.