BackgroundMannanase is an enzyme that can catalyze random hydrolysis of beta-1,4-mannosidic linkages in the main chain of mannans, glucomannans and galactomannans which are the key polymers in hemicellulose. It has been used in a number of different industrial applications including food, feed, pharmaceutical, pulp/paper industries, and second generation biofuel. To optimize the expression system of mannanase Man23 gene, two kinds of vectors and host bacteria were determined and compared.ResultsRecombinants pHY-p43-man23 and pBPS-man23 were constructed and transferred into Bacillus subtilis WB600 and Brevibacillus brevis respectively. For mannanase Man23 gene, recombinant pHY-p43-man23 expressed in Brevibacillus brevis had higher production and activity. Compared to the wild-type Bacillus subtilis B23, the production of recombinant pHY-p43-man23 in B. brevis increased by 10 times and activity increased by 21.3%. pHY-p43-man23 in B. brevis had activity at the range of 20 ~ 70°C but its optimum temperature was 50°C and had activity from pH 4 ~ 10 but its optimum pH was around 7. This demonstrated the recombinant had improved stability as well.ConclusionsMannanase is an important industrial enzyme and combination of vector pHY-p43 and host Brevibacillus brevis is a novel expression system for a mannanase decoding gene. This work aims at exploring a better expression system of mannanase Man23 decoding gene for industrial application.

N-terminal truncation had positive effects on the thermostability and activity of mannanase.

A novel chemically modified electrode has been prepared on the basis of the attachment of multi-wall carbon nanotubes (MWNT) onto the surface of a glassy carbon electrode (GCE) in the presence of a hydrophobic surfactant, dihexadecyl phosphate (DHP). This MWNT film was characterized by transmission electron microscopy images (TEM) and scanning electron microscopy (SEM). The electrochemical behavior of tyrosine at the MWNT film coated GCE was examined and it is found that this MWNT-modified GCE greatly enhances the oxidation peak current of tyrosine. Effects of some important factors, including pH, scan rate and amount of modifier, on the oxidation process of tyrosine were investigated. When the signal to noise ratio (SNR) is 3, the detection limit is 1 x 10(-7) M. The low relative standard deviations of the detection of tyrosine in human morning urine (3.3%) and white wine (5.2%) suggest a good reproducibility of the modified electrode.

TiEV is an autonomous driving platform implemented by the Tongji University of China. The vehicle is driveby-wire and is fully powered by electricity. We devised the software system of TiEV from scratch, which is capable of driving the vehicle autonomously in urban paths as well as on fast express roads. We describe our whole system, especially novel modules of probabilistic perception fusion, large-scale mapping and updating, the 1 st and the 2 nd planning and the overall safety concern. TiEV finished 2016, and 2017 Intelligent Vehicle Future Challenge of China held at Changshu. We show our experiences on the development of autonomous vehicles and discuss the future trends.

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