Properties of Selected Hemicellulases of a Multi-Enzymatic System from Penicillium funiculosum

Screening of Lactic Acid Bacteria Strains for Potential Sourdough and Bread Applications: Enzyme Expression and Exopolysaccharide Production

Twenty-eight strains of lactic acid bacteria (LAB) were characterized for the ability to express enzymes of interest (including protease, xylanase, α-amylase, laccase, and glucose oxidase) as well as the ability to produce exopolysaccharide (EPS). The screening of enzyme capability for all LAB strains proceeded in a progressive 3-stage manner that helps to profile the efficiency of LAB strains in expressing chosen enzymes (Stage 1), highlights the strains with affinity for flour as the substrate (Stage 2), and discerns strains that can adapt well in a simulated starter environment (Stage 3). The theoretical ability of LAB to express these enzymes was also assessed using Basic Local Alignment Search Tool (BLAST) analysis to identify the underlying genes in the whole genome sequence. By consolidating both experimental data and information obtained from BLAST, three LAB strains were deemed optimal in expressing enzymes, namely, Lb. delbrueckii subsp. bulgaricus (RBL 52), Lb. rhamnosus (RBL 102), and Lb. plantarum (ATCC 10241). Meanwhile, EPS-producing capabilities were observed for 10 out of 28 LAB strains, among which, Lactococcus lactis subsp. diacetylactis (RBL 37) had the highest total EPS yield (274.15 mg polysaccharide/L culture) and produced 46.2% polysaccharide with a molecular mass of more than 100 kDa.

The ileal and total tract digestibility fibre and nutrients in pigs fed high-fibre cereal-based diets provided without and with a carbohydrase complex

The effect of carbohydrase can be variable according to the complexity of cereal grains and co-products. Studies on the effect of carbohydrase on cereal diets varying in complexity are scarce. This study was conducted to investigate the apparent ileal (AID) and total tract digestibility (ATTD) of energy, fibre and nutrients in pigs fed diets based on cereal grains and co-products without and with supplementation with a carbohydrase complex in the form of xylanase, arabinofuranosidase and β-glucanase. The experiment was carried out as an 8 × 4 Youden Square design (eight diets and four periods by two blocks) using 16 growing pigs (33.3 ± 0.8 kg) surgically fitted with a T-cannula in the terminal ileum. The pigs were fed eight experimental diets based on either - maize, wheat, rye, or a wheat and rye mix that were provided with or without enzyme supplementation. The AID and ATTD of DM, organic matter, energy, CP, fat, starch, and soluble and insoluble non-starch polysaccharides (NSPs) were studied using titanium dioxide as an indigestible marker. There was a cereal type effect (P < 0.05) of the AID of most of the nutrients investigated but ash and NSP and some of its constituents but with no interactions between cereal types and carbohydrase supplementation (P > 0.05). The ATTD of nutrients in the large intestine was mainly influenced by the fibre composition and was significantly lower (P < 0.001) for NSP, protein and energy for the Maize than the other diets. Supplementation of the cereal diets with the carbohydrase complex partially degrades arabinoxylan (AX) and β-glucan giving rise to a generally higher AID of high-molecular weight arabinoxylan (P = 0.044), starch (P = 0.042), a tendency (P < 0.10) of higher AID of non-cellulosic polysaccharide glucose residue (β-glucan) and soluble arabinoxylan (AX) whereas none of the other components were affected (P > 0.05). Collectively, the results indicate that the carbohydrase complex degrades AX in the stomach and small intestine, leading to a higher AID but with no influence on the ATTD of fibres, nutrients, and energy.

A review of limitations to using cassava meal in poultry diets and the potential role of exogenous microbial enzymes

Cassava (Manihot esculenta), a crop grown in the tropics, is increasingly becoming a vital feed resource for human beings and livestock. Traditionally, cassava has been used primarily as a source of food for humans. However, it is becoming an increasingly important ingredient in livestock feed. The use of cassava leaves and roots in poultry diets is limited because of nutrient imbalances and toxins (hydrogen cyanide (HCN)) found in them. High HCN is reduced to innocuous levels by processing the ingredient using a simple sun drying method. Plant fibre content can be reduced and made available for use by poultry through the use of exogenous enzymes. More recent innovative interventions in biotechnology have brought about various exogenous enzymes that can help improve the digestibility of fibrous diets. These include, among others, carbohydrases, proteases and phytases. The extent to which the animals utilise nutrients is influenced by the type of enzyme and the physicochemical properties of the feed ingredient. This review aims to collate information on the current state of knowledge on the use of exogenous microbial enzymes in diets containing cassava and how the enzymes that target carbohydrates might be useful in making nutrient available for poultry.

Optimization of β-mannanase production by Bacillus subtilis US191 using economical agricultural substrates

The Bacillus subtilis US191 strain producing highly thermostable β-mannanase was previously selected as potential probiotic candidate for application as feed supplement in poultry industry. Initially, the level of extracellular β-mannanase production by this strain was 1.48 U ml^-1 . To improve this enzyme titer, the present study was undertaken to optimize the fermentation conditions through experimental designs and valorization of agro-industrial byproducts. Using the Plackett-Burman design, in submerged fermentation, a set of 14 culture variables was evaluated in terms of their effects on β-mannanase production. Locust bean gum (LBG), soymeal, temperature, and inoculum size were subsequently optimized by response surface methodology using Box-Behnken design. Under optimized conditions (1 g L^-1 LBG, 8 g L^-1 soymeal, temperature of 30°C and inoculum size of 10¹⁰  CFU ml^-1 ), a 2.59-fold enhancement in β-mannanase titer was achieved. Next, to decrease the enzyme production cost, the effect of partial substitution of LBG (1 g L^-1 ) by agro-industrial byproducts was investigated, and a Taguchi design was applied. This allowed the attaining of a β-mannanase production level of 8.75 U ml^-1 in presence of 0.25 g L^-1 LBG, 5 g L^-1 of coffee residue powder, 5 g L^-1 of date seeds powder, and 5 g L^-1 of prickly pear seeds powder as mannans sources. Overall, a 5.91-fold improvement in β-mannanase production by B. subtilis US191 was achieved.

Next-generation non-starch polysaccharide-degrading, multi-carbohydrase complex rich in xylanase and arabinofuranosidase to enhance broiler feed digestibility

This study was carried out to evaluate the effect of a multi-carbohydrase complex (MCC) rich in xylanase (Xyl) and arabinofuranosidase (Abf) on overall broiler feed digestibility in broilers. Energy utilization and digestibility of dry matter (DM), organic matter (OM), protein, starch, fat, and insoluble and soluble fibers were measured using the mass-balance method. The experiment was carried out on 120 broilers (3-week-old chickens). Broilers were distributed over 8 treatments to evaluate the effect of the dietary arabinoxylan content and nutrient density with and without MCC (Rovabio® Advance). The graded content of arabinoxylan (AX) was obtained using different raw materials (wheat, rye, barley, and dried distillers' wheat). Diet-energy density was modified with added fat. Measurements indicated that nutrient density and AX content had a significant effect on most digestibility parameters. Apparent metabolizable energy (AME) was significantly increased (265 kcal kg-1) by MCC. The addition of MCC also resulted in significant improvement in the digestibility of all evaluated nutrients, with average improvements of 3.0, 3.3, 3.2, 3.0, 6.2, 2.9, 5.8, and 3.8% units for DM, OM, protein, starch, fat, insoluble and soluble fibers, and energy utilization, respectively. The interaction between MCC and diet composition was significant for the digestibility of OM, fat, protein, and energy. Nutrient digestibility and diet AME were negatively correlated with AX content (P < 0.001). However, the addition of MCC resulted in a reduction of this negative effect (P < 0.001). The AME of diets with and without the addition of MCC were successfully predicted by the diet digestible nutrient (i.e., starch, protein, fat, insoluble and soluble fibers) content with and without MCC (R2 = 0.87; RSD = 78 kcal kg-1). This study confirms that the presence of AX in wheat-based diets and wheat-based diets with other cereals and cereal by-products reduces nutrient digestibility in broiler chickens. Furthermore, the dietary addition of MCC, which is rich in Xyn and Abf, reduced deleterious effect of fiber and improved overall nutrient digestibility in broiler diets.

Quantitative multiplexed profiling of Penicillium funiculosum secretome grown on polymeric cellulase inducers and glucose

Filamentous fungi respond to the need to secure utilisable carbon from their growth milieu by secreting unique extracellular proteins depending upon the types of polymeric substrates. We have here profiled the variations in the secretome pattern of a non-model hypercellulolytic fungus - Penicillium funiculosum, grown in minimal media containing four different polymeric cellulase inducers, i.e., Avicel, wheat bran, ammonium-pretreated wheat straw and Avicel & wheat bran, and glucose over its early and late log phases of growth. Of the 137 secreted proteins validated at 1% FDR, we identified the quantified proteins in three clusters as early, persistently or lately expressed. The type of carbon substrate present in the culture media significantly affected the levels of cellulolytic enzymes expression by the fungus. The top abundant proteins quantified in the secretome for Avicel and wheat bran were cellobiohydrolaseI [GH7-CBM1], cellobiohydrolaseII [GH6-CBM1], β-glucosidase [GH3], arabinofuranosidase [GH51] and β-xylosidase [GH3], with bicupin being highest in case of wheat straw. Our results further suggested that the fungus secreted the extracellular proteins in waves, such that the initial responders act to hydrolyse the composite substrates in the culture environment before the second wave of proteins which tend to be more tailored to the specific substrate in the cultivating media.

BIOLOGICAL SIGNIFICANCE

In this article, we have comprehensively examined the dynamics of the secretome of a non-model hypercellulolytic fungus produced in response to model and composite cellulase inducers. Our study has provided additional insights into how the fungus enzyme machinery responds to the presence of different polymeric cellulase inducers over the two different growth phases (early growth and late growth phase). The comprehensive typing and quantification of the different proteins present in the secretomes of the cellulolytic fungal strains in response to diverse nutrient sources hold many prospects in understanding the fungus unique enzyme machinery and dynamics for the downstream biotechnological applications.

Effects of dietary supplementation of exogenous multi-enzyme mixture containing carbohydrases and phytase on growth performance, energy and nutrient digestibility, and selected mucosal gene expression in the small intestine of weanling pigs fed nutrient deficient diets

Effect of carbohydrases and phytase supplementation on growth performance, nutrient utilization and gut health of nursery pigs was evaluated. Pigs were blocked by body weight (BW) and sex and allocated to four treatments. Treatments were a positive control (PC), a negative control (NC) deficient in metabolizable energy (ME), crude protein (CP), Ca, and non-phytate P (nPP), NC plus Rovabio® Max AP enzyme mix, at 0.05 and 0.075 g kg−1. Apparent total tract digestibility (ATTD) was determined in faecal samples. Apparent ileal digestibility (AID) was determined in ileal digesta samples collected after euthanasia. Lower final BW and average daily gain (ADG) (P < 0.05) were observed in NC compared with PC. Enzyme at 0.05 g kg−1increased (P < 0.05) BW on d 14 and d 41, respectively, and also increased ADG. Enzyme at 0.075 g kg−1increased BW on d 14 and ADG on d 0 to d 14 (P < 0.05). Feed efficiency [gain to feed ratio (G:F)] was greater (P < 0.05) in PC than NC from d 15 to d 41 and from d 0 to d 41. No difference in G:F was observed with enzyme supplementation. Higher (P < 0.05) serum Ca and bone ash were observed in PC than NC. Enzyme increased the ATTD of Ca and P (P < 0.05) compared with NC.

Enzymatic generation of galactose-rich oligosaccharides/oligomers from potato rhamnogalacturonan I pectic polysaccharides

Potato pulp by-product rich in galactan-rich rhamnogalacturonan I (RG I) was investigated as a new source of oligosaccharides with potential prebiotic properties. The efficiency of selected monocomponent enzymes and multi-enzymatic preparations to generate oligosaccharides/oligomers from potato RG I was evaluated. These overall results of yield were dependent on the activity profile of the multi-enzymatic preparations. Highest oligo-RG I yield of 93.9% was achieved using multi-enzymatic preparation (Depol 670L) with higher hydrolytic activity toward side chains of RG I as compared to its backbone. Main oligo-RG I products were oligosaccharides with DP of 2-12 (79.8-100%), while the oligomers with DP of 13-70 comprised smaller proportion (0.0-20.2%). Galactose (58.9-91.2%, w/w) was the main monosaccharide of oligo-RG I, while arabinose represented 0.0-12.1%. An understanding of the relationship between the activity profile of multi-enzymatic preparations and the yield/DP of oligo-RG I was achieved. This is expected to provide the capability to generate galacto- and galacto(arabino) oligosaccharides and their corresponding oligomers from an abundant by-product.

Proteomics Insights into the Biomass Hydrolysis Potentials of a Hypercellulolytic Fungus Penicillium funiculosum

The quest for cheaper and better enzymes needed for the efficient hydrolysis of lignocellulosic biomass has placed filamentous fungi in the limelight for bioprospecting research. In our search for efficient biomass degraders, we identified a strain of Penicillium funiculosum whose secretome demonstrates high saccharification capabilities. Our probe into the secretome of the fungus through qualitative and label-free quantitative mass spectrometry based proteomics studies revealed a high abundance of inducible CAZymes and several nonhydrolytic accessory proteins. The preferential association of these proteins and the attending differential biomass hydrolysis gives an insight into their interactions and clues about possible roles of novel hydrolytic and nonhydrolytic proteins in the synergistic deconstruction of lignocellulosic biomass. Our study thus provides the first comprehensive insight into the repertoire of proteins present in a high-performing secretome of a hypercellulolytic Penicillium funiculosum, their relative abundance in the secretome, and the interaction dynamics of the various protein groups in the secretome. The gleanings from the stoichiometry of these interactions hold a prospect as templates in the design of cost-effective synthetic cocktails for the optimal hydrolysis of biomass.

Impact of exogenous carbohydrases and phytase on growth performance and nutrient digestibility in broilers

Lu, H., Adedokun, S. A., Preynat, A., Legrand-Defretin, V., Geraert, P. A., Adeola, O. and Ajuwon, K. M. 2013. Impact of exogenous carbohydrases and phytase on growth performance and nutrient digestibility in broilers. Can. J. Anim. Sci. 93: 243–249. The effect of supplementing corn–soybean-based diets with Rovabio®Max AP, an exogenous enzyme mix with carbohydrase (xylanase and β-glucanase) and phytase activities to broiler chickens was evaluated. Male Ross 708 broilers were assigned to four diets: positive control (PC), negative control (NC), deficient in metabolizable energy (ME), crude protein (CP), calcium (Ca) and non-phytate phosphorus (nPP), relative to the PC, by 100 kcal kg−1, 5 g kg−1, 1.1 g kg−1and 1.6 g kg−1, respectively, in the starter and grower diets; and NC+Rovabio®at 0.05 or 0.075 g kg−1diet. Starter diets were fed from day 0 to day 21 and grower diets from day 22 to day 42. Body weight (BW) and body weight gain on days 22 and 42 were increased (P<0.05) by enzyme supplementation. Enzyme addition increased (P<0.05) feed intake from day 22 to day 42 and overall (day 0 to day 42). Gain to feed ratio (G:F) was significantly increased (P<0.05) with enzyme supplementation during both starter and grower phases. Enzyme addition increased (P<0.05) serum phosphorus (P) concentration on day 21. On day 42 enzyme supplementation increased (P<0.05) the apparent ileal digestibility of P, dry matter (DM), energy, and N. Addition of a combination of carbohydrases (xylanase and β-glucanase) and phytase to corn–soybean-based diets deficient in ME, CP, Ca and P resulted in a significant increase in growth performance and utilization of P, DM, energy and N in broiler chickens.

An integrative in vitro approach to analyse digestion of wheat polysaccharides and the effect of enzyme supplementation

The digestion of polysaccharides from the wheat cultivars Caphorn and Isengrain was investigated, and the efficiency of an enzyme preparation was tested using the TNO gastrointestinal model (TIM-1). The apparent digestibility (AD) of carbohydrates was determined based on the measurement of organic matter (OM), total monosaccharides, reducing ends (RE) and end products (EP: glucose, maltose and xylobiose). The AD of the OM from Caphorn and Isengrain measured using caecectomised cockerels did not differ from that measured using TIM-1: 72.0 (SD 2.6) v. 70.6 (SD 0.6) % for Caphorn (P = 0.580) and 73.0 (SD 2.3) v. 71.1 (SD 1.9) % for Isengrain (P = 0.252). After the 6 h TIM-1 digestion, 41.4-58.9 % of the OM, RE and EP were recovered from the jejunal compartment and 18.3-27.1 % from the ileal compartment, while ileal deliveries and digestive residues constituted the remainder. A commercial enzyme cocktail tested at 0.2 μl/g of wheat improved TIM-1 digestibility of Caphorn and Isengrain polysaccharides: 3.9 % (P = 0.0203) and 3.4 % (P = 0.0058) based on the OM; 9.7 % (P < 0.0001) and 3.1 % (P = 0.031) based on the total glucose; 47.2 % (P < 0.0001) and 14.2 % (P = 0.0004) based on the RE, respectively. The enzyme cocktail improved the release of the EP for Caphorn (3.8 %, P = 0.008) but not for Isengrain ( − 0.8 %, P = 0.561). The higher efficiency of the enzyme supplementation on the digestion of Caphorn polysaccharides compared with Isengrain seems to be linked to the higher soluble carbohydrate contents and/or less ramified arabinoxylan of Caphorn.

Wheat-barley-rye- or corn-fed growing pigs respond differently to dietary supplementation with a carbohydrase complex

Thirty-six pigs (22 kg of BW) were used to evaluate a carbohydrase preparation, with xylanase and β-glucanase as main activities, added to either wheat-barley-rye- (WBR) or corn-based diets on performance, intestinal environment, and nutrient digestibility. Pigs were offered 1 of 4 different dietary treatments for 27 d according to a factorial arrangement of treatments (a 2 × 2) with 2 cereal types (WBR or corn) and 2 levels of supplemental carbohydrase (0 or 0.01%). Pig growth and feed intake were individually measured every week until the end of the experiment when pigs were slaughtered to obtain samples of digesta and tissues. Cereal type affected performance only during wk 1, in which WBR improved ADG (590 vs. 440 g/d; P = 0.008) and G:F (0.61 vs. 0.43; P = 0.045) compared with corn. The WBR also increased the viscosity of the digestive contents in stomach (1.95 vs. 1.23 mPa·s; P = 0.001) and ileum (6.53 vs. 2.80 mPa·s; P = 0.001) and resulted in greater cecal starch digestibility (95.7 vs. 93.9%; P = 0.012). However, trends for a reduction in digestibility were observed for glucose in the nonstarch polysaccharide (NSP) fraction in the ileum (64.4 vs. 75.8%; P = 0.074) and galactose in the NSP fraction in the cecum (1.4 vs. 1.8%; P = 0.055). The use of the enzyme preparation increased ADFI during wk 2 (1,328 vs. 1,215 g/d; P = 0.028), and increased villus height (423 vs. 390 µm; P = 0.045) and tended to reduce relative pancreas weight (0.16 vs. 0.17% BW; P = 0.079) at d 27. The enzyme also improved cecal starch digestibility (95.5 vs. 94.1%; P = 0.043) and tended to improve ileal energy digestibility (61.3 vs. 53.7%; P = 0.090) and cecal glucose digestibility in the NSP fraction (76.0 vs. 54.5%; P = 0.055). However, it reduced the cecal digestibility of mannose in the NSP fraction (27.0 vs. 50.5%; P = 0.016). Interactions (P < 0.05) between cereal type and enzyme supplementation were observed for ADG and G:F during wk 2, BW and ADG during wk 3, and BW and ADFI over the whole trial; and also for villus-height-to-crypt-depth ratio and for cecal DM digestibility. In all instances, whereas the added enzyme had no effect in the case of the corn diet, improvements were observed with WBR. In conclusion, the multi-enzyme tested had different effects depending on the type of cereal present in the diet.

High-level expression of a novel Penicillium endo-1,3(4)-β-d-glucanase with high specific activity in Pichia pastoris

A novel endo-1,3(4)-β-d-glucanase gene (bgl16C1) from Penicillium pinophilum C1 was cloned and sequenced. The 945-bp full-length gene encoded a 315-residue polypeptide consisting of a putative signal peptide of 18 residues and a catalytic domain belonging to glycosyl hydrolase family 16. The deduced amino acid sequence showed the highest identity (82%) with the putative endo-1,3(4)-β-glucanase from Talaromyces stipitatus ATCC 10500 and 60% identity with the characterized β-1,3(4)-glucanase from Paecilomyces sp. FLH30. The gene was successfully overexpressed in Pichia pastoris. Recombinant Bgl16C1 constituted 95% of total secreted proteins (2.61 g l−1) with activity of 28,721 U ml−1 in a 15-l fermentor. The purified recombinant Bgl16C1 had higher specific activity toward barley β-glucan (12,622 U mg−1) than all known glucanases and also showed activity against lichenan and laminarin. The enzyme was optimally active at pH 5.0 and 55°C and exhibited good stability over a broad acid and alkaline pH range (&gt;85% activity at pH 3.0–7.0 and even 30% at pH 11.0). All these favorable enzymatic properties make it attractive for potential applications in various industries.