Kraft pulp enzymatic hydrolysis is a promising method of woody biomass bioconversion. The influence of composition and structure of kraft fibers on their hydrolysis efficiency was evaluated while using four substrates, unbleached hardwood pulp (UHP), unbleached softwood pulp (USP), bleached hardwood pulp (BHP), and bleached softwood pulp (BSP). Hydrolysis was carried out with Penicillium verruculosum enzyme complex at a dosage of 10 filter paper units (FPU)/g pulp. The changes in fiber morphology and structure were visualized while using optical and electron microscopy. Fiber cutting and swelling and quick xylan destruction were the main processes at the beginning of hydrolysis. The negative effect of lignin content was more pronounced for USP. Drying decreased the sugar yield of dissolved hydrolysis products for all kraft pulps. Fiber morphology, different xylan and mannan content, and hemicelluloses localization in kraft fibers deeply affected the hydrolyzability of bleached pulps. The introduction of additional xylobiase, mannanase, and cellobiohydrolase activities to enzyme mixture will further improve the hydrolysis of bleached pulps. A high efficiency of never-dried bleached pulp bioconversion was shown. At 10% substrate concentration, hydrolysates with more than 50 g/L sugar concentration were obtained. The bioconversion of never-dried BHP and BSP could be integrated into working kraft pulp mills.

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The aim of the present work was to analyze the taxonomic diversity in the Kombucha bacterial consortium during long-term cultivation in the North (Arctic) of the European part of Russia. The high-performance sequencing showed that 99.1 % of the bacterial fraction of the fresh 7-d culture was Proteobacteria of mostly cellulose-producing genera with the order Acetobacterales being dominant and represented by the Komagataeibacter (87.3 %) and Gluconobacter (6.3 %). Aging of the Kombucha bacterial consortium from 20 to 90-d cultivation lead to the reduction of number of cellulose-producing bacteria and intense growth of cellulolytic bacteria including Clostridiales, Bacteroidetes, Actinomyces. Also the acidophilic microorganisms have been detected. The long-term growth of the Kombucha bacterial consortium can be considered as a succession of microbial communities.