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The full utilization of hemicellulose sugars (pentose and exose) present in lignocellulosic material, is required for an efficient bio-based fuels and chemicals production. Two recombinant thermophilic enzymes, an endo-1,4-β-mannanase from Dictyoglomus turgidum (DturCelB) and an α-galactosidase from Thermus thermophilus (TtGalA), were assayed at 80 °C, to assess their heterosynergystic association on galactomannans degradation, particularly abundant in hemicellulose. The enzymes were tested under various combinations simultaneously and sequentially, in order to estimate the optimal conditions for the release of reducing sugars. The results showed that the most efficient degree of synergy was obtained in simultaneous assay with a protein ratio of 25% of DturCelB and 75% of TtGalA, using Locust bean gum as substrate. On the other hand, the mechanism of action was demonstrated through the sequential assays, i.e. when TtGalA acting as first to enhance the subsequent hydrolysis performed by DturCelB. The synergistic association between the thermophilic enzymes herein described has an high potential application to pre-hydrolyse the lignocellulosic biomasses right after the pretreatment, prior to the conventional saccharification step.

Abstract The additive Hemicell®‐L is a liquid preparation of endo‐1,4‐β‐mannanase that is authorised as a zootechnical feed additive for chickens for fattening. The applicant has requested the renewal of the authorisation, new uses and the modification of the manufacturing process including the change of the production strain. The new production strain is a genetically modified strain of Paenibacillus lentus obtained from a strain that has been evaluated previously by EFSA and considered to be safe. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) evaluated the genetic modification and concluded that the sequences introduced to obtain the production strain did not raise safety concerns. The production strain and its DNA were not detected in the additive. The Panel concluded that the additive is safe for chickens for fattening and turkeys for fattening at the recommended level. These conclusions were extended or extrapolated to the other target species under application. The Panel concluded that the results obtained in the toxicological studies performed with the fermentation products of the recipient strain and of another genetically modified strain obtained from the same recipient strain could support the safety for the consumer of the product obtained with the new production strain. The additive is not a dermal or eye irritant and it is not a dermal sensitiser. However, considering that the active substance is a protein, the additive should be regarded as a potential sensitiser. The Panel concluded that the additive has a potential to be efficacious as a zootechnical additive for the target species at 79,200 U/kg.

Background Endo-1,4-β-mannanase is an enzyme that can catalyze the random hydrolysis of β-1, 4- mannosidic linkages in the main chain of mannans, glucomannans and galactomannans and has a number of applications in different biotechnology industries. Penicillium oxalicum is a powerful hemicellulase-producing fungus (Bioresour Technol 123:117-124, 2012); however, few previous studies have focused on the cloning and expression of the endo-1,4-β-mannanase gene from Penicillium oxalicum. Results A gene encoding an acidophilic thermostable endo-1,4-β-mannanase (E.C. 3.2.1.78) from Penicillium oxalicum GZ-2, which belongs to glycoside hydrolase family 5, was cloned and successfully expressed in Pichia pastoris GS115. A high enzyme activity (84.4 U mL-1) was detected in the culture supernatant. The recombinant endo-1,4-β-mannanase (rPoMan5A) was tagged with 6 × His at its C-terminus and purified using a Ni-NTA Sepharose column to apparent homogeneity. The purified rPoMan5A showed a single band on SDS-PAGE with a molecular mass of approximately 61.6 kDa. The specific activity of the purified rPoMan5A was 420.9 U mg-1 using locust bean gum as substrate. The optimal catalytic temperature (10 min assay) and pH value for rPoMan5A are 80°C and pH 4.0, respectively. The rPoMan5A is highly thermostable with a half-life of approximately 58 h at 60°C at pH 4.0. The Km and Vmax values for locust bean gum, konjac mannan, and guar gum are 7.6 mg mL-1 and 1425.5 μmol min-1 mg-1, 2.1 mg mL-1 and 154.8 μmol min-1 mg-1, and 2.3 mg mL-1 and 18.9 μmol min-1 mg-1, respectively. The enzymatic activity of rPoMan5A was not significantly affected by an array of metal ions, but was inhibited by Fe3+ and Hg2+. Analytical results of hydrolytic products showed that rPoMan5A could hydrolyze various types of mannan polymers and released various mannose and manno-oligosaccharides, with the main products being mannobiose, mannotriose, and mannopentaose. Conclusion Our study demonstrated that the high-efficient expression and secretion of acid stable and thermostable recombinant endo-1, 4-β-mannanase in Pichia pastoris is suitable for various biotechnology applications. [ABSTRACT FROM AUTHOR]

The additive Hemicell®‐L is a liquid preparation of endo‐1,4‐β‐mannanase that is authorised as a zootechnical feed additive for chickens for fattening. The applicant has requested the renewal of the authorisation, new uses and the modification of the manufacturing process including the change of the production strain. The new production strain is a genetically modified strain of Paenibacillus lentus obtained from a strain that has been evaluated previously by EFSA and considered to be safe. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) evaluated the genetic modification and concluded that the sequences introduced to obtain the production strain did not raise safety concerns. The production strain and its DNA were not detected in the additive. The Panel concluded that the additive is safe for chickens for fattening and turkeys for fattening at the recommended level. These conclusions were extended or extrapolated to the other target species under application. The Panel concluded that the results obtained in the toxicological studies performed with the fermentation products of the recipient strain and of another genetically modified strain obtained from the same recipient strain could support the safety for the consumer of the product obtained with the new production strain. The additive is not a dermal or eye irritant and it is not a dermal sensitiser. However, considering that the active substance is a protein, the additive should be regarded as a potential sensitiser. The Panel concluded that the additive has a potential to be efficacious as a zootechnical additive for the target species at 79,200 U/kg. [ABSTRACT FROM AUTHOR]

The additive Hemicell ® -L is a liquid preparation of endo-1,4-β-mannanase that is authorised as a zootechnical feed additive for chickens for fattening. The applicant has requested the renewal of the authorisation, new uses and the modification of the manufacturing process including the change of the production strain. The new production strain is a genetically modified strain of Paenibacillus lentus obtained from a strain that has been evaluated previously by EFSA and considered to be safe. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) evaluated the genetic modification and concluded that the sequences introduced to obtain the production strain did not raise safety concerns. The production strain and its DNA were not detected in the additive. The Panel concluded that the additive is safe for chickens for fattening and turkeys for fattening at the recommended level. These conclusions were extended or extrapolated to the other target species under application. The Panel concluded that the results obtained in the toxicological studies performed with the fermentation products of the recipient strain and of another genetically modified strain obtained from the same recipient strain could support the safety for the consumer of the product obtained with the new production strain. The additive is not a dermal or eye irritant and it is not a dermal sensitiser. However, considering that the active substance is a protein, the additive should be regarded as a potential sensitiser. The Panel concluded that the additive has a potential to be efficacious as a zootechnical additive for the target species at 79,200 U/kg., (© 2019 European Food Safety Authority. EFSA Journal published by John Wiley and Sons Ltd on behalf of European Food Safety Authority.)