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This study characterizes a cryptic (pro)phage-related sequence within the Caldibacillus debilis GB1 genome, designated CBP1.CBP1 is a Siphoviridae-like genome highly related to GBVS1 from Geobacillus sp. 6k51. The CBP1genome is a 37,315 bp region containing 69 putative ORFs with a GC content of 42% flanked on both sides by host DNA integrated into the main bacterial chromosome (contig 16). Bioinformatic analyses identified cassettes of genes within the CBP1 genome that were similar in function, yet distinct in sequence, from genes previously identified in GBVS1. All of CBP1 genes had less than 60% amino acid sequence identity with GBVS1by tBLASTx, with the exception of the TMP repeat gene. CBP1 possessed all the necessary genes to undergo a temperate/lytic phage life cycle, including excision, replication, structural genes, DNA packaging, and cell lyses. Proteomic analysis of CBP1 revealed the expression of 5 proteins. One of the expressed proteins was a transcriptional regulator protein homologous to the bacteriophage λ repressor protein (cI) expressed in high amounts from the CBP1 region, consistent with a lysogenic phage in a repressed state. The CBP1 protein expression profile during host growth provides unique insight into thermophilic Siphoviridae-like phages in the repressed state within their host cells. [ABSTRACT FROM AUTHOR]

Aromatic alcohols (including β-phenylethanol, tyrosol and tryptophol) could contribute positively to the aroma flavor of huangjiu at an appropriate amount. In this study, it was found that the aromatic alcohols in huangjiu were predominantly synthesized by Saccharomyces cerevisiae HJ01. The Ehrlich pathway and shikimate pathway, including 31 genes, are responsible for aromatic alcohol biosynthesis in S. cerevisiae. During the first 120 h of huangjiu fermentation, the genes GAP1 HJ01 (permease), BAT2 HJ01 (transaminase), PDC1 HJ01 and PDC5 HJ01 (pyruvate decarboxylase), and ADH1 HJ01 (alcohol dehydrogenase) formed integrated Ehrlich pathway are responsible for aromatic alcohol biosynthesis. In S. cerevisiae HJ01, the mutations in the promoter region of genes GAP1 HJ01, BAT2 HJ01, PDC1 HJ01, and PDC5 HJ01 involved in the Ehrlich pathway increased the promoter strength and transcriptional levels of related genes. The addition of 20 U/g acid protease could substantially increase the expression levels of genes involved in the Ehrlich pathway, and therefore there were 34.7% increasing for the concentration of total aromatic alcohols. • Aromatic alcohols in huangjiu are synthesized by Saccharomyces cerevisiae. • Aromatic alcohols in huangjiu are mainly synthesized through the Ehrlich pathway. • Key genes and promoter mutations in Ehrlich pathway were identified. • Acid protease enhanced expression level of key genes. [ABSTRACT FROM AUTHOR]