Search

The comprehensive utilization of agro-industrial residues poses a persistent global challenge. Microbial fermentation is an efficient way to convert agro-industrial residues into valuable products. Trichoderma reesei is a traditional cellulase and other protein producer using agro-industrial residues as substrates. The potential of T. reesei as a chassis to produce small natural products remains untapped. Here, we successfully employed T. reesei to efficiently synthesize different terpene types. To optimize the chassis for metabolite synthesis, we deleted major (hemi-)cellulase genes along with the global regulator Lae1 to improve the efficiency of secondary metabolite biosynthesis, and overexpressed the constitutively activated transcriptional factor XYR1A824V in MC3 (a uridine auxotrophic strain derived from T. reesei Rut-C30) to alleviate glucose repression. Through glucose, lactose, and corn steep as substrates, the production of ophiobolin F using the modified chassis was increased to 1187.06 mg L−1 in shake flask fermentation and up to 3072.45 mg L−1 under fed-batch fermentation. We further demonstrated the versatility of the Δlae1::xyr1/MC3-Δ10 chassis by successfully producing other fungal and plant terpenes. Collectively, our results demonstrated the potential of the Reducing Outflow and Broadened Upstream Substrate Type (ROBUST) T. reesei chassis for efficient terpene production utilizing agro-industrial residues, with important implications for terpene biosynthesis and sustainable biofabrication. [ABSTRACT FROM AUTHOR]

Covering: up to July 2023 Terpene cyclases (TCs) catalyze some of the most complicated reactions in nature and are responsible for creating the skeletons of more than 95 000 terpenoid natural products. The canonical TCs are divided into two classes according to their structures, functions, and mechanisms. The class II TCs mediate acid–base-initiated cyclization reactions of isoprenoid diphosphates, terpenes without diphosphates (e.g., squalene or oxidosqualene), and prenyl moieties on meroterpenes. The past twenty years witnessed the emergence of many class II TCs, their reactions and their roles in biosynthesis. Class II TCs often act as one of the first steps in the biosynthesis of biologically active natural products including the gibberellin family of phytohormones and fungal meroterpenoids. Due to their mechanisms and biocatalytic potential, TCs elicit fervent attention in the biosynthetic and organic communities and provide great enthusiasm for enzyme engineering to construct novel and bioactive molecules. To engineer and expand the structural diversities of terpenoids, it is imperative to fully understand how these enzymes generate, precisely control, and quench the reactive carbocation intermediates. In this review, we summarize class II TCs from nature, including sesquiterpene, diterpene, triterpene, and meroterpenoid cyclases as well as noncanonical class II TCs and inspect their sequences, structures, mechanisms, and structure-guided engineering studies. [ABSTRACT FROM AUTHOR]

First reported in 2004, and subsequently advanced by Chemat's team and other research teams in the following two decades, the use of D -limonene as a natural product extraction solvent offers multiple benefits that go beyond its environmentally benign nature. Following a review of the main research achievements concerning the use of this biosolvent in the extraction of widely different natural products, we offer a comprehensive perspective including usually neglected economic and safety aspects. The study concludes by identifying three main research outcomes and providing two guidelines to bioeconomy practitioners willing to use this terpene in new natural production extraction and production processes. [ABSTRACT FROM AUTHOR]