Transcriptome and proteome of the corm, leaf and flower of Hypoxis hemerocallidea (African potato).

The corm of Hypoxis hemerocallidea, commonly known as the African potato, is used in traditional medicine to treat several medical conditions such as urinary infections, benign prostate hyperplasia, inflammatory conditions and testicular tumours. The metabolites contributing to the medicinal properties of H. hemerocallidea have been identified in several studies and, more recently, the active terpenoids of the plant were profiled. However, the biosynthetic pathways and the enzymes involved in the production of the terpene metabolites in H. hemerocallidea have not been characterised at a transcriptomic or proteomic level. In this study, total RNA extracted from the corm, leaf and flower tissues of H. hemerocallidea was sequenced on the Illumina HiSeq 2500 platform. A total of 143,549 transcripts were assembled de novo using Trinity and 107,131 transcripts were functionally annotated using the nr, GO, COG, KEGG and SWISS-PROT databases. Additionally, the proteome of the three tissues were sequenced using LC-MS/MS, revealing aspects of secondary metabolism and serving as data validation for the transcriptome. Functional annotation led to the identification of numerous terpene synthases such as nerolidol synthase, germacrene D synthase, and cycloartenol synthase amongst others. Annotations also revealed a transcript encoding the terpene synthase phytoalexin momilactone A synthase. Differential expression analysis using edgeR identified 946 transcripts differentially expressed between the three tissues and revealed that the leaf upregulates linalool synthase compared to the corm and the flower tissues. The transcriptome as well as the proteome of Hypoxis hemerocallidea presented here provide a foundation for future research.

Streptomyces albulus yields ε-poly-L-lysine and other products from salt-contaminated glycerol waste.

Actinomycetes are the most important microorganisms for the industrial production of secondary metabolites with antimicrobial and anticancer properties. However, they have not been implicated in biorefineries. Here, we study the ability of the ε-poly-L-lysine producing Streptomyces albulus BCRC 11814 to utilize biodiesel-derived crude glycerol. S. albulus was cultured in a mineral medium supplemented with up to 10% w/v sodium chloride or potassium chloride, and with crude glycerol as the sole carbohydrate source. Under these conditions, the strain produced 0.1 g ε-poly-L-lysine per 1 g of biomass. RNA sequencing revealed upregulation of the ectoine biosynthetic pathway of S. albulus, which provides proof of halotolerance. S. albulus has several silent secondary metabolite biosynthetic clusters predicted within the genome. Based on the results, we conclude that S. albulus BCRC 11814 is a halotolerant microorganism capable of utilizing biodiesel-derived crude glycerol better than other actinomycetes included in the present study. S. albulus has the potential to be established as microbial platform production host for a range of high-value biological products.

Monitoring on-line desalted lignocellulosic hydrolysates by microdialysis sampling micro-high performance anion exchange chromatography with integrated pulsed electrochemical detection/mass spectrometry.

An on-line system based on microdialysis sampling (MD), micro-high performance anion exchange chromatography (micro-HPAEC), integrated pulsed electrochemical detection (IPED), and electrospray ionization mass spectrometry (MS) for the monitoring of on-line desalted enzymatic hydrolysates is presented. Continuous monitoring of the enzymatic degradation of dissolving pulp from Eucalyptus grandis as well as degradation of sugar cane bagasse in a 5-mL reaction vessel was achieved up to 24 h without any additional sample handling steps. Combining MD with micro-HPAEC-IPED/MS and on-line desalting of hydrolysates enabled injection (5 microL) of at least 23 samples in a study of the sequential action of hydrolytic enzymes in an unmodified environment where the enzymes and substrate were not depleted due to the perm-selectivity of the MD membrane (30 kDa cut-off). Xylanase, phenolic acid esterase and a combination of endoglucanase (EG II) with cellobiohydrolase (CBH I) resulted in the production of DP 1 after the addition of esterase, DP 2 and DP 3 after the addition of EG II and CBH I, from the dissolving pulp substrate. Similar sequential enzyme addition to sugar cane bagasse resulted in DP 1 production after the addition of esterase and DP 1, DP 2 and DP 3 production after the addition of the EG II and CBH I mixture. Combining MS on-line with micro-HPAEC-IPED proved to be a versatile and necessary tool for such a study compared to conventional methods. The mass selectivity of MS revealed complementary information, including the co-elution of saccharides as well as the presence of more than one type of DP 2 in the case of dissolving pulp and several types of DP 2 and DP 3 for sugar cane bagasse. This study demonstrates the limitation of the use of retention time alone for confirmation of the identity of saccharides especially when dealing with complex enzymatic hydrolysates. In situ sampling and sample clean-up combined with on-line desalting of the chromatographic effluent, provides a generic approach to achieve real time monitoring of enzymatic hydrolysates when they are detected by a combination of IPED and MS.