(3S)-Acetoin and (2S,3S)-2,3-butanediol are important platform chemicals widely applied in the asymmetric synthesis of valuable chiral chemicals. However, their production by fermentative methods is difficult to perform. This study aimed to develop a whole-cell biocatalysis strategy for the production of (3S)-acetoin and (2S,3S)-2,3-butanediol from meso-2,3-butanediol. First, E. coli co-expressing (2R,3R)-2,3-butanediol dehydrogenase, NADH oxidase and Vitreoscilla hemoglobin was developed for (3S)-acetoin production from meso-2,3-butanediol. Maximum (3S)-acetoin concentration of 72.38 g/L with the stereoisomeric purity of 94.65% was achieved at 24 h under optimal conditions. Subsequently, we developed another biocatalyst co-expressing (2S,3S)-2,3-butanediol dehydrogenase and formate dehydrogenase for (2S,3S)-2,3-butanediol production from (3S)-acetoin. Synchronous catalysis together with two biocatalysts afforded 38.41 g/L of (2S,3S)-butanediol with stereoisomeric purity of 98.03% from 40 g/L meso-2,3-butanediol. These results exhibited the potential for (3S)-acetoin and (2S,3S)-butanediol production from meso-2,3-butanediol as a substrate via whole-cell biocatalysis.

In this study, a novel laccase gene (Lcc1) from Ganoderma tsugae was isolated and its functions were characterized in detail. The results showed that Lcc1 has the highest expression activity during mycelium development and fruit body maturation based on the analysis of Lcc1 RNA transcripts at different developmental stages of G. tsugae. To investigate the exact contribution of Lcc1 to mycelium and fruit body development in G. tsugae, Lcc1 transgenic strains were constructed by targeted gene replacement and over-expression approaches. The results showed that the lignin degradation rate in Lcc1 deletion mutant was much lower than the degradation efficiency of the wild-type (WT), over-expression and rescue strains. The lignin degradation activity of G. tsugae is dependent on Lcc1 and the deletion of Lcc1 exerted detrimental influences on the development of mycelium branch. Furthermore, the study uncovered that Lcc1 deletion mutants generated much shorter pale grey fruit bodies, suggesting that Lcc1 contributes directly to pigmentation and stipe elongation during fruit body development in G. tsugae. The information obtained in this study provides a novel and mechanistic insight into the specific role of Lcc1 during growth and development of G. tsugae.

In this study, fresh Lyophyllum decastes was dried using hot air drying (HAD), hot air combined with vacuum drying (HAVD), and vacuum freeze drying (VFD). Additionally, the quality and volatile compounds were analyzed. VFD achieved the best color retention, the highest rehydration capacity, and the slightest damaged tissue structure; however, it recorded the longest drying time and the highest energy consumption. HAD was the most energy-efficient of the three methods. Furthermore, the products with more hardness and elasticity were obtained by HAD and HAVD—this finding was convenient for transportation. In addition, GC-IMS demonstrated that the flavor components had significantly changed after drying. A total of 57 volatile flavor compounds was identified, and the aldehyde, alcohol, and ketone compounds were the primary ingredient of the L. decastes flavor component, whereby the relative content of the HAD sample was apparently higher than HAVD and VFD. Taken together, VFD was better at preserving the color and shape of fresh L. decastes, but HAD was more appropriate for drying L. decastes because of the lower energy consumption, and was more economical. Meanwhile, HAD could be used to produce a more intense aroma.

Two main adenoviral diseases have been described in pigeons: pigeon adenovirus type 1 (PiAdV-1) and pigeon adenovirus type 2 (PiAdV-2), which belong to the genus Aviadenovirus under the family Adenoviridae. PiAdV-1 and PiAdV-2 are highly pathogenic to pigeons, leading to considerable losses worldwide. To date, there is little information on the epidemiological distribution of PiAdV-1 and PiAdV-2 in pigeons due to the lack of detection and differentiation platforms for these two viruses. High-resolution melting technology (HRM) has been widely used for developing detection and differentiation platforms, with the melting profile based on the GC content in the real-time PCR (qPCR-HRM) system. This study designed and synthesized a pair of specific primers on the basis of the characteristic variations of the 52K genes of PiAdV-1 and PiAdV-2, then the detection and differentiation qPCR-HRM platform was established after conditional optimization. The results showed that this method had good specificity; it could only specifically detect PiAdV-1 and PiAdV-2, with no cross-reaction with other pigeon-origin pathogens that occur in pigeons. This method had high sensitivity, with the lowest detection limits at 57 copies/µL (for PiAdV-1) and 56 copies/µL (for PiAdV-2). This method had good intra-group and inter-group coefficients of variation, both of which were less than 1.5%. Field samples for the epidemiological surveillance and investigation data of PiAdV-1 and PiAdV-2 were checked. We found only PiAdV-2-positive samples in meat pigeons, but the percentages of PiAdV-1-positive, PiAdV-2-positive, and coinfection-positive samples among the racing pigeons were 5.71%, 14.29%, and 2.86%, respectively. To our knowledge, this is the first report for the simultaneous detection and differentiation of PiAdV-1 and PiAdV-2 using the qPCR-HRM platform. Our study also provided evidence of PiAdV-1 and PiAdV-2 coinfection in racing pigeons, but further studies are needed.