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Biosynthesis of n -caproate from waste streams rich in acetate and ethanol through chain elongation has offered a potentially sustainable way for future production of liquid biofuels. However, most of the waste streams that fit with the purpose (e.g., digestate) are also rich in ammonium which at high concentration may cause toxic effects on the bioconversion process. This study aims to develop a robust, efficient, and cost-effective chain elongation process with high caproate productivity and tolerance to high ammonia concentration, through immobilization of Clostridium kluyveri on biomass particles as immobilization material. The threshold ammonia concentration for suspended cells cultivation was 2.1 g/L, while it was higher than 5.0 g/L for the wheat straw immobilized system. The caproate production process was dependent on the selected carriers and was performing in the order of: wheat straw > grass straw > saw dust. The biofilm immobilized on the wheat straw showed good reuse capability for caproate production under high ammonia concentration. Moreover, the lag phase for caproate production was shortened from 72 to 30 h after 8 times reuse. These results proved that caproate production and tolerance of chain elongation to ammonia toxicity could be enhanced via cell immobilization. This study offers insight into future development of efficient and cost-effective chain elongation system for production of caproate and other value-added products. Unlabelled Image • Boosted caproate production by cell immobilization on wheat straw • Shortened lag phase from 104 to 15 h after immobilization for chain elongation • The highest caproate production of 10.1 g/L was achieved with immobilized cells. • The immobilized cells as biofilm showed good stability and productivity. [ABSTRACT FROM AUTHOR]

Wheat bran was tested as the solid substrate for the tray-type solid-state fermentation (SSF) production of polygalacturonase (PG) enzyme by A. sojae mutant strain – a high-PG activity producer. PG production of A. sojae was found to reduce as the thickness of the substrate increase from 8 mm to 14 mm at 90% relative humidity. An interaction between the thickness of the bed and relative humidity of the environment was determined with the help of experimental design and statistical analysis tools. As a result, the PG activity could be enhanced by 31% as the process conditions optimized. Additionally, 11 mm thickness and 70% relative humidity were selected as the PG production favoring conditions with the maximum PG activity of 298 U/g substrate in tray type of SSF without the addition of any nutritive or inducing supplements into wheat bran. The kinetic study conducted in the trays revealed the presence of reduction in the water activity on the 4th day of the SSF process under stated conditions. The productivity of the process conducted under optimized conditions was 3.41 U/g substrate −1 h −1 for the 4th day of the SSF. [ABSTRACT FROM AUTHOR]

Abstract: Biochemical conversion of lignocellulose to fermentable carbohydrates for ethanol production is now being implemented in large-scale industrial production. Applying hydrothermal pretreatment and enzymatic hydrolysis for the conversion process, a residue containing substantial amounts of lignin will be generated. So far little is known about the composition of this lignin residue which at present is mainly incinerated for heat and power generation and not yet converted so much into more valuable products. In this study, the structural and chemical composition of the solid and liquid fractions of lignin residue from wheat straw were analysed and processing factors discussed. Roughly 70 and 15% of the solid mass fraction consisted of lignin and ash, respectively. Residual carbohydrates mostly originated from hemicellulose in the liquid fraction and from cellulose in the solid fraction. The solid fraction also contained significant amounts of protein, which is a valuable by-product when used as animal feed or when enzymes and yeast cells are separated for process recycling. Silica was the dominant constituent in the mineral fraction and except for few fragments of lignified middle lamellae most particles in the solid fraction appeared as silica coated by lignin, hampering separation of the two components before incineration or refinement of the residue. [Copyright &y& Elsevier]

[Display omitted] • Enantioselective fate of pydiflumetofen (PYD) was observed in wheat. • R -PYD was more easily accumulating in wheat roots and translocating to shoots. • A total of 9 metabolites of PYD were detected in wheat roots and shoots. • PYD was uptake via symplastic pathway, dominated by aquaporin and anion channels. • Ta LTP 1.1 and CYP71C6v1 revealed the enantioselective fate of PYD in wheat. Pydiflumetofen (PYD), a highly effective and broad-spectrum fungicide, is commonly employed for the control of fungal diseases. In this study, the uptake, translocation, and biotransformation of PYD by wheat (Triticum aestivum L.) were firstly investigated at a chiral level. The findings revealed that the residue concentration of R -PYD in wheat was higher than that of S -PYD, because of its higher uptake rate (k 1 = 0.0421 h−1) and lower elimination rate (k2 = 0.0459 h−1). Additionally, R -PYD exhibited higher root bioconcentration factors and translocation factors compared with S- enantiomer, indicating R -PYD was more easily accumulating in roots and translocating to shoots. Furthermore, a total of 9 metabolites, including hydroxylated, demethylated, demethoxylated, dechlorinated, hydrolyzed, and glycosylated-conjugated products, were detected qualitatively in wheat roots or shoots. Symplastic pathway-mediated uptake, which predominantly relied on aquaporins and anion channels, was confirmed by root adsorption and inhibition experiments, without displaying any enantioselective effect. Molecular simulations demonstrated that R -PYD exhibited stronger binding affinity with Ta LTP 1.1 with a lower grid score (−6.79 kcal/mol), whereas weaker interaction with the metabolic enzyme (CYP71C6v1) compared to the S- enantiomer. These findings highlight the significance of plant biomacromolecules in the enantioselective bioaccumulation and biotransformation processes. Importantly, a combination of experimental and theoretical evidence provide a comprehensive understanding of the fate of chiral pesticides in plants from an enantioselective perspective. [ABSTRACT FROM AUTHOR]

Abstract: The fine specialty chemicals production from agro-industrial by-products such as cereal bran is a topic of high interest in wheat-producing countries. In this work, the possibility of obtaining vanillin from bioconversion of ferulic acid derived from enzymatic hydrolysis of wheat bran was explored. Freely available ferulic acid was first obtained through wheat bran hydrolysis by using commercially available, technical-grade enzyme preparations. Then, resting cells of an engineered E. coli strain, JM109(pBB1), containing the genes responsible for conversion of ferulic acid into vanillin, were used to transform ferulic acid available in the hydrolyzed mixture into vanillin. A vanillin molar yield of 50% was obtained, but most of the vanillin produced was reduced to vanillyl alcohol. The purification of the hydrolyzate with a ionic exchange resin to remove most of the carbohydrates allowed to obtain both higher bioconversion yields (up to 70%) and lower vanillin reduction. This is the first work in which vanillin is produced from ferulic acid obtained through wheat bran hydrolysis. The results obtained demonstrate the potential application of the proposed strategy in vanillin biosynthesis from agro-industrial by-products. [Copyright &y& Elsevier]

Abstract: The conversion of wheat straw to fermentable sugar for bioethanol production typically involves a thermal pretreatment step, followed by enzymatic hydrolysis. In this study we have investigated the effect of steam explosion parameters on wheat straw digestibility using a newly designed steam explosion unit and a process without acid impregnation. The wheat straw was steam pretreated using 18 different conditions in the temperature range of 170–220 °C and the resulting material was used directly (i.e. without washing) for enzymatic hydrolysis and fermentation in either a separate hydrolysis and fermentation (SHF)-type or a simultaneous saccharification and fermentation (SSF)-type set-up. Maximum glucose yields upon enzymatic hydrolysis were obtained after pretreatment at 210 °C for 10 min and yields were similar at harsher conditions. Xylose yields increased with temperature and residence time up to 190 °C, but decreased at harsher pretreatment conditions since these led to xylan degradation and concomitant production of furfural. In an SHF-type set-up ethanol formation did not follow enzymatic glucose release and was inversely correlated with furfural levels. An SFF-type set-up displayed a straightforward correlation between the expected amount of released glucose and the ethanol yields. The highest saccharification yields corresponded to about 90% of the cellulose in the substrate. Overall, this study shows that steam explosion without an acid catalyst is a good pretreatment method for saccharification of wheat straw. Optimal steam explosion conditions need to be a compromise between sugar accessibility and sugar degradation. [Copyright &y& Elsevier]

Abstract: A chronology of reactor design from laboratory scale to pilot scale for the bioconversion of wheat straw to animal feed is presented. The engineering criteria considered at each stage of development are discussed. Designs were executed at each stage and their performance was compared based on engineering and bioconversion parameters. Illustrative detailed analyses of data obtained from performance evaluation experiments from selected designs are provided. Schematics diagrams of the different generations of reactor designs are also presented. [Copyright &y& Elsevier]

Eco-friendly alternative way for waste straw management is needed. Black soldier fly (Hermetia illucens) larvae (BSFL) are outstanding insects for bioconversion of organic waste, which can convert separate or mixed waste, i.e. manure, kitchen waste and straw, into biomass rich in protein and fat. In this study, through orthogonal experiment, maize straw, fermented with Aspergillus oryzae for 24 h in a ratio of 4000:1, was identified for BSFL bioconversion. Bioconversion performance of BSFL on fermented maize straw was assessed. With this fermented maize straw as feedstuff, larval stage of BSF was significantly prolonged compared with the control feedstuff (wheat bran). Adult duration was significantly shortened and the fecundity of females was significantly decreased. The harvested dry BSF larvae contained 41.76% crude protein, 30.55%, crude fibre, and 8.24% crude ash. The grease of BSFL, compared to the larvae collected from the control diet, had a higher proportion of monounsaturated fatty acid (24.86%) and polyunsaturated fatty acid (25.37%), while a lower proportion of saturated fatty acid (45.41%). Dry matter reduction of maize straw was 48.41%. After bioconversion by BSFL, the residual maize straw was significantly changed in crude protein, crude fat and nitrogen free extract content. By comparing with organic fertilizer NY525-2012, maize straw residue had a potential application in agriculture and nursery as a novel fertilizer. This new alternative method will benefit the comprehensive bioconversion of maize straw with pretreatment by insect. • The optimum fermentation conditions for bioconversion by the black soldier flies was determined. • BSF fed on fermented maize straw had a similar development performance compared to wheat bran feedstuff. • BSFL fed on fermented maize straw had higher content of unsaturated fatty acids compared to wheat bran feedstuff. • Residue maize straw bioconversion by black soldier flies can be used as organic fertilizer. [ABSTRACT FROM AUTHOR]

Abstract: In traditional cereal-based industrial processes, component separation is often incomplete resulting in a residue of mixed macromolecules including largely starch, protein, phytic acid and many others. The development of a viable cereal-based biorefinery would involve effective bioconversion of cereal components for the production of a nutrient-complete fermentation feedstock. Simultaneous starch and protein hydrolysis represents an effective approach to the production of platform chemicals from wheat. Solid state fermentations of wheat pieces and waste bread by Aspergillus oryzae and Aspergillus awamori have been combined in this study to enhance starch and protein hydrolysis. Kinetic studies confirmed that the proteolytic enzymes from A. oryzae introduced no negative effect on the stability of the amylolytic enzymes from A. awamori under the optimal conditions for starch hydrolysis. When applied to hydrolyse wheat flour, the enzyme solution from A. awamori converted nearly all of the starch into glucose and 23% of the total nitrogen (TN) into free amino nitrogen (FAN). Under the same reaction conditions the enzyme solution from A. oryzae hydrolysed 38% of the protein but only 18.5% of the starch. A mixture of the two enzyme solutions hydrolysed 34.1% of the protein, a 1.5-fold increase from that achieved by the enzyme solution from A. awamori, while maintaining a near completion of starch hydrolysis. [Copyright &y& Elsevier]

To achieve the high-level stable expression of chlorothalonil hydrolytic dehalogenase (Chd), the gene chd was first integrated into the chromosome of Bacillus subtilis WB800. High generation stability was achieved by almost no gene lost after six generations but Chd activity decreased. aprE promoter alteration, translation initiation region modification and multi-copy chromosome integration were studied and these modifications could increase Chd activity by 270%, 2304% and 25%. Chlorothalonil residual exhibited inhibition on bioconversion of lignocellulosic biomass. The addition of Chd crude enzyme (60 μL per g wheat straw) could increase glucose production by 36.10% and 39.65% in synergistic hydrolysis and separate hydrolysis by laccase and cellulase with 120 mg/L residual chlorothalonil. Filter paper activity and carboxymethyl cellulase activity were enhanced by 12.84% and 23.95%, and biomass of Trichoderma reesei was increased by 76.67% under 50 μg chlorothalonil/g dry straw in solid-state fermentation. Thus, the high-level stable expressed Chd effectively eliminated chlorothalonil inhibition on enzymatic hydrolysis and solid-state fermentation. It showed promising potential for bioremediation of chlorothalonil pollution and improving conversion efficiency of lignocellulose. [ABSTRACT FROM AUTHOR]

The characterization of cellulase performance for industrial-scale processes holds special challenges. A huge gap exists between the enzyme characterization in a laboratory and large-scale process performances. Common cellulase mixtures from Novozymes and enzymes provided by Moscow State University were used to hydrolyze wheat straw, grass, pine wood, and aspen wood. Glucose yields from the enzymatic hydrolysis of the raw materials were investigated as a function of cellulase enzyme loading and of particle sizes with different solid loading. The particle size had a significant effect on glucose yield, while the used enzyme concentration had a much smaller effect. Hydrolyses of sets of wheat straw particles were used to introduce a substrate-specific kinetic enzyme unit. The data were also used to generate an empirical model in order to predict the glucose yield on the basis of the Sauter mean diameter of the feedstocks. [ABSTRACT FROM AUTHOR]

Abstract Second generation bioconversion industry is a driver towards the post-petroleum age where materials and fuels are made of renewable resources. Agricultural residues are a promising feedstock source for emerging bioeconomic concepts. Research on the forecasting of feedstock potentials is still scarce and available methodologies are not harmonised. Biomass markets are characterised by their regionality, which requires regionalised assessments and forecasting of feedstock potentials. This work dealt with the question of the variables that determine the future development of agricultural harvesting residues. It further examines methodologies allowing a spatially explicit prediction of feedstock potentials. The forecasting approach was applied to wheat straw, corn stover, barley straw, and rapeseed straw, which together account for 80 per cent of cereals and oil crops harvesting residues in the European Union. The results indicate the largest increase of all investigated crops was for corn stover at up to 20 per cent between 2017 and 2030. Barley straw potentials are expected to stay rather constant within the coming decade. Rapeseed is the only crop likely to face a decreasing production in many regions in the coming years. This work identified increasing crop yields as the main driver for advancing feedstock potentials. Especially Central and Eastern European countries show high growth rates. The methodology of the research work contributes to the discussions about sustainable resource potentials of the European bioeconomy. The forecasting results can be used for strategic decision-making in emerging bioconversion concepts. Highlights • Spatially explicit assessment of agricultural residue potentials in the EU. • Time series-based forecast until 2030. • Focused on wheat straw, corn stover, barley straw and rape straw. • Developed forecasting methodology is transferable to other biomass feedstock. [ABSTRACT FROM AUTHOR]

Lignocellulose degradation is a challenging step for value added products and biofuels production. Cellulomonas fimi secretes complex mixtures of carbohydrate active enzymes (CAZymes) which synergistically degrade cellulose and hemicelluloses. Their characterization may provide new insights for enzymatic cocktails implementation. Bioinformatic analysis highlighted 1127 secreted proteins, constituting the in silico secretome, graphically represented in a 2DE map. According to Blast2GO functional annotation, many of these are involved in carbohydrates metabolism. In vivo secretomes were obtained, growing C. fimi on glucose, CMC or wheat straw for 24 h. Zymography revealed degradative activity on carbohydrates and proteomic analysis identified some CAZymes, only in secretomes obtained with CMC and wheat straw. An interaction between cellobiohydrolases is proposed as a strategy adopted by soluble multimodular cellulases. Such approach can be crucial for a better characterization and industrial exploitation of the synergism among C. fimi enzymes. [ABSTRACT FROM AUTHOR]

To achieve a waste-free clean production, the present study aimed to valorize an underused agroindustrial byproduct (rice bran) by mealworms bioconversion and produce bio-oil from pyrolysis of insect excreta (frass) as bioinsecticide. To reach the first goal, the suitability of rice bran (RB) versus standard diet, wheat bran (WB), was examined by determining feed conversion, growth performance, and nutritional profile of T. molitor larvae. RB diet was an appropriate feed substrate for breeding mealworms, as evidenced by their high survival rates, optimal feed conversion parameters, and its capability to support the growth and life cycle of this insect. Besides, RB did not affect soluble larval protein content but modified crude fat content and fatty acid profile. In order to address the second aim, egested frass from RB and WB were subjected to pyrolysis to obtain bio-oils. The main compound was acetic acid (≈37%) followed by 1,6-anhydro-β-d-glucopyranose (from 16 to 25%), as measured by GC-MS analysis. Nitrogen-containing chemicals accounted for ≈10%. Frass bio-oils could represent a novel source of bioinsecticides due to their bioeffectiveness in insect pests of economic importance (Plodia interpunctella and Tribolium castaneum) and medical interest (Culex pipiens pipiens). For P. interpunctella adults, frass bio-oils produced insecticidal activity by fumigant and contact exposure whereas for T. castaneum adults, just fumigant. By a miniaturized model that simulates semireal storage conditions, it was seen that, on T. castaneum , frass RB bio-oil generated higher repellent effect than frass WB. Finally, bio-oils proved to have larvicidal activity against Cx. p. pipiens. [Display omitted] • This work investigates mealworm bioconversion coupled to bioinsecticide production. • RB as suitable feed substrate for T. molitor development. • This is first report on the insecticidal activity of bio-oils from frass pyrolysis. • Frass bio-oils induce lethal effects on insect of economic and medical interest. • Simulating semireal storage conditions, frass bio-oils produce repellent effect. [ABSTRACT FROM AUTHOR]

This study reported an environment friendly process for xylitol bioconversion from corncob hemicellulose hydrolysate prepared through xylanolytic enzymes by adapted Candida tropicalis . In order to improve the production of xylanolytic enzymes from Aspergillus terreus , the fermentation medium and growth conditions were optimized. Maximum xylanase (722 U/g) and β-xylosidase (196 U/g) production were exhibited on wheat bran and corncob (mass ratio of 7:3) medium supplemented with 2% (v/v) NaNO 3 and 0.05% (v/v) Tween 80 at pH 6.8, 1:1 (v/w) moisture level, 20% inoculum level and 30 °C for 120 h of cultivation. For preparation of corncob hemicellulose hydrolysate, the optimum enzymatic hydrolysis conditions contained enzyme dosage (30.6 U/g), water addition (19.2 mL/g), temperature (48.01 °C), pH (5.75). Under these conditions, the sugars of 18.03 g/L xylose and 4.87 g/L glucose were obtained in 8 h. The corncob hemicellulose hydrolysate was used for xylitol fermentation and the maximum xylitol yield of 75.14% was obtained by adapted C. tropicalis after the optimization of fermentation. [ABSTRACT FROM AUTHOR]

The open culture system exhibits several advantages in bioconversion of complex substrates into caproate, yet it is urgent to develop an advanced approach to overcome the low fermentative efficiency. In this study, three reinforcement techniques were employed to reinforce the chain elongation in the open culture system, including bioaugmentation, pretreatment of anaerobic sludge (AS) and addition of cell carrier. Results showed that the caproate production was improved to 48.9 mmol/L using bioaugmentation technology. With removal of methanogen by alkaline-thermal pretreatment, the caproate production increased to 94.8 mmol/L. The highest caproate production of 130.5 mmol/L was obtained with addition of cell carrier, which was explained by the formation of biofilm. The genus Clostridium_sensu_stricto capable of medium chain fatty acids production dominated the microbiome of the AS. This study provides an insight that efficient caproate production can be achieved in the open culture system by reinforcing the pathway of chain elongation. [Display omitted] • Caproate production was improved in the open culture system. • Acetate competition was reduced via eliminating acetoclastic methanogen. • The biofilm on the cell carrier reinforced the pathway of chain elongation. • The genus Clostridium_sensu_stricto dominated the microbiome of anaerobic sludge. [ABSTRACT FROM AUTHOR]

Background: Vitamin A (VA) and zinc deficiencies are prevalent. Maize is a common staple, and milling affects nutrient and nutrient-modifier profiles.Objective: We investigated the interaction of maize milling methods (i.e., whole grain compared with refined) in male Mongolian gerbils aged 29-35 d with conventionally bred provitamin A-biofortified (orange) or white maize on VA and zinc status.Methods: Study 1 (n = 67) was a 2 × 3 milling (whole compared with refined) by VA [no-vitamin A placebo group (VA-), orange, and VA-supplemented group (VA+)] design, with 4 wk of VA depletion followed by six 4-wk treatments (n = 10/treatment). Study 2 (n = 33) was a 2 × 2 milling-by-zinc [no-zinc placebo group (Zn-) compared with zinc-supplemented group (Zn+)] design, including 2 wk of VA depletion followed by four 3-wk treatments (n = 8-9/treatment). For study 1, positive and negative control groups were given supplemental VA at equimolar amounts to β-carotene equivalents consumed by the orange groups (74 ± 5 nmol/d) or placebo, respectively. For study 2, positive and negative control groups were given 152 μg Zn/d or placebo, respectively.Results: Milling significantly affected zinc concentration, providing 44-45% (whole grain) or 9-14% (refined) NRC requirements. In study 1, orange maize improved liver VA concentrations (mean ± SD: 0.28 ± 0.08 μmol/g) compared with the white maize groups (0.072 ± 0.054 μmol/g). Provitamin A bioefficacy was similar. In study 2, neither zinc nor milling influenced liver retinol. Refined Zn- gerbils weighed less than others by day 14 (46.6 ± 7.1 compared with 56.5 ± 3.5 g, respectively; P < 0.0001). Milling affected pancreas zinc concentrations (refined Zn-: 21.1 ± 1.8 μg Zn/g; whole Zn-: 32.5 ± 5.8 μg Zn/g).Conclusions: Whole-grain intake improved zinc and did not affect provitamin A bioefficacy. Other factors affected by milling (e.g., shelf life, preference, aflatoxin fractioning) need to be considered to maximize health. [ABSTRACT FROM AUTHOR]