Due to the awareness of fossil fuel depletion and global warming, biorefinery for production of biofuels and valuable platform chemicals from lignocellulosic biomass has attracted growing interest in the past decades. With the rising concept of comprehensive utilization of lignocellulosic biomass,fractionation processes are generally necessary prior to its subsequent conversion with aims to produce purified cellulose with specific recovery of hemicellulose and lignin. In this review, ionic liquids fractionation,steam explosion based fractionation,twin-screw extrusion and organosolv fractionation are described and their features and comparative performances are discussed.

Previous studies showed that γ-aminobutyric acid (GABA) can protect some GABA-producing bacteria against acid stress through glutamate decarboxylation. However, the acid stress mechanism is a comprehensive network related to numerous genes and proteins. Other than the Glutamate Decarboxylase (GAD)/GABA antiporter system, limited information is available about the physiological modifications that occur in Lactobacillus brevis during GABA production under acidic conditions. Therefore, this study aims to investigate the physiological modifications that occur in a GABA-producing L. brevis NCL912 during GABA production under acidic conditions. The differential protein expression of L. brevis NCL912 under different culture conditions was determined by using proteome analysis. Eleven of the protein spots were identified by mass spectrometry. Among the 11 proteins, 10 were upregulated, whereas one was downregulated. The function of downregulated protein was unknown. The upregulated proteins were involved in stress response, protein synthesis, quorum sensing, glycolysis and membrane lipid synthesis. Stress response, protein synthesis, glycolysis-related proteins are general acid stress proteins, while LuxS-dependent quorum sensing system and membrane lipid synthesis-related proteins might be induced by sodium L-glutamate during GABA production under acid stress. In conclusion, sodium L-glutamate might trigger other acid-tolerance responses, except the GAD/GABA system in L. brevis NCL912 during GABA production under acidic conditions.

β-chitosan preparation from squid pens was carried out using aqueous NaOH with the ultrasonic assistance. Single factor experiments and L9(34) orthogonal experiments were used to investigate the effect of three parameters (reaction time, concentration of NaOH and reaction temperature) on deacetylation of β-chitin. The optimal conditions for deacetylation of chitin were reaction temperature 80°C, reaction time 2 h and concentration of NaOH 50%. The optimal conditions allowed deacetylation degree of β-chitin from 71.32% to 92.91%. The β-chitosan from squid pens was confirmed by Fourier transform infrared spectroscopy. The antibacterial activities of the prepared β-chitosans againstaphylococcus aureus(S. aureus) andEscherchia coli(E.coli) were then determined and compared by the MIC (minimum inhibitory concentration). Results indicate that β-chitosans with different degrees of deacetylation (DD) possess different antibacterial activity. The growth ofS. aureuscan be easily inhibited by prepared β-chitosan thanE.coli.

Levulinic acid (LA) is a new versatile platform chemical derived from renewable non-food biomass. A major challenge in the purification of LA from biomass hydrolysate is the separation of LA and formic acid. A novel granular activated carbon (GAC) adsorption and separation of LA and formic acid were investigated in this work. Adsorption equilibria elucidated that LA preferentially adsorbed onto GAC than formic acid. Mixed solution of LA and formic acid was fed into the GAC packed-bed at 30°C, then formic acid was washed out from the column in a pure form with 60°C water and finally LA was effectively eluted with 95% (v/v) ethanol at 60°C. LA can be completely separated from formic acid by this simple GAC adsorption process with good yield and high purity.

The transformation conditions of the protoplasts from Trichoderma viride mediated by restriction enzyme were studied in this paper. The optimum generation conditions of protoplasts were as followed: 8 mg/ml glucanex was added into the phosphate buffer (pH 6.98), the mycelial that cultured for 24 hr was hydrolyzed for 4 hr at 30°C under 40 r/min shaking speed. The protoplast yield was 4.7×107 cfu/mg. The regeneneration rate of protoplast was 14.5% on CM medium contained 0.3 mol/L KCl and 0.3 mol/L Inositol. Transformants were obtained by transfering hygromycin B resistance gene into T. viride by restriction enzyme mediated integration (REMI), The preliminary identification of the transformants indicated that the exogenous gene had been integrated into T. viride genome.