The α-galactosidase-coding gene agaAJB13 was cloned from Sphingomonas sp. JB13 showing 16S rDNA (1,343 bp) identities of ≤97.2% with other identified Sphingomonas strains. agaAJB13 (2,217 bp; 64.9% GC content) encodes a 738-residue polypeptide (AgaAJB13) with a calculated mass of 82.3 kDa. AgaAJB13 showed the highest identity of 61.4% with the putative glycosyl hydrolase family 36 α-galactosidase from Granulicella mallensis MP5ACTX8 (EFI56085). AgaAJB13 also showed <37% identities with reported protease-resistant or Sphingomonas α-galactosidases. A sequence analysis revealed different catalytic motifs between reported Sphingomonas α-galactosidases (KXD and RXXXD) and AgaAJB13 (KWD and SDXXDXXXR). Recombinant AgaAJB13 (rAgaAJB13) was expressed in Escherichia coli BL21 (DE3). The purified rAgaAJB13 was characterized using p-nitrophenyl-α-D-galactopyranoside as the substrate and showed an apparent optimum at pH 5.0 and 60 o C and strong resistance to trypsin and proteinase K digestion. Compared with reported proteaseresistant α-galactosidases showing thermolability at 50 o C or 60 o C and specific activities of <71 U/mg with or without protease treatments, rAgaAJB13 exhibited a better thermal stability (half-life of >60 min at 60 o C) and higher specific activities (225.0-256.5 U/mg). These sequence and enzymatic properties suggest AgaAJB13 is the first identified and characterized Sphingomonas α-galactosidase, and shows novel protease resistance with a potential value for basic research and industrial applications.

An experiment was conducted to study the influence of isoamylase supplementation to maize-soybean diets on productive performance and amylase activities of broilers from 1 to 42 d of age.The results showed that different dose of isoamylase（300g/T,600 g/T,900 g/T, containing 3000IU of isoamylase/g）in the maize - soybean meal diet significantly affected the performance of broilers within 1-42 days. Within 1-21 days , the average daily gain(ADG) of experimental groups( experiment I (E I) experiment II (E II) experiment III (E III) ) improved by 3.2% -10.32%(P>0.05) compared with the control groups(negative control(NC) and positive control(PC)), average daily feed intake(ADFI) improved by 0.63%-7.43%(P>0.05), while feed conversion ratio decreased by 0.55%-4.43%(P>0.05); Within 21-42 days , the ADG of experimental groups decreased by 1.38%-4.84% and ADFI by 11.89%-15.58% (P<0.05), feed conversion ratio by 5.41%-7.54% compared with that in the NC group; Within 1-42 days , the ADG of experimental groups improved by 0.54%-4.06%(P>0.05), while ADFI decreased by 0.75%-11.83% (P<0.05), and feed conversion ratio by 3.97%-7.52% (P>0.05) compared with those in the negative control. Isoamylase supplementation influenced amylase activity of various parts of the chyme in digestive tract and the tissues of small intestine and pancreas. 21 d, the amylase activity in experimental groups improved by 4.67%-79.29%(P<0.05) compared with PC, α-amylase activity in the majority experimental groups were lower than PC group, but the difference was not significant(P>0.05).

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This study employed statistically based on experimental designs to optimize transesterification conditions for biodiesel production from waste oil via lipase-catalyzed in homoeothermy. Optimization of different reaction parameters were done by using response surface methodology. Results indicated optimum conditions including: alcohol to oil molar ratio 3:1, lipase concentration 58.38 U each gram of oil, water and n-hexane content were 24.59% and 13.28% respectively, reaction temperature at 20 °C , and reaction time for 24 h. Under these optimal conditions, 98.24% yield of biodiesel was obtained. This study will probably contribute to the development of continuous enzymatic processes, and maybe a suitable method for industrial production of biodiesel.

Many archaebacteria are strictly dependent upon H2 for their ATP production. Moreover, for many methanogens (the strictly lithoautotrophic forms), H2O, CO2 and acetate are the sole source of both energy and carbon, all of which are waste products of the symbionts anaerobic metabolism. The fact that methanogens associate with hydrogen-producing organisms means endosymbiotic methanogens cling not to free-living eubacteria, but hydrogenosomes themselves in the cytosol of amitochondriate protists. This has given rise to the theory that the eukaryotic cell originated from syntrophic interactions between bacteria and archaea. We call this new hypothesis for the origin of eukaryotic cells as hydrogen hypothesis.