CARBOHYDRATE POLYMERS
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2016
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IF 4.219
Honghua Jia,Tingting Shao,Chao Zhong,Hengxiang Li,Min Jiang,Hua Zhou,Ping Wei
In this paper, we produced hemicellulosic hydrolysate from corncob by tetrabutylammonium hydroxide (TBAH) extraction and dilute acid hydrolysis combined, further evaluating the feasibility of the resultant corncob hemicellulosic hydrolysate used in xylitol production by Candida tropicalis . Optimized conditions for corncob hemicellulose extraction by TBAH was obtained via response surface methodology: time of 90 min, temperature of 60 °C, liquid/solid ratio of 12 (v/w), and TBAH concentration of 55%, resulting in a hemicellulose extraction of 80.07% under these conditions. The FT-IR spectrum of the extracted corncob hemicellulose is consistent with that of birchwood hemicellulose and exhibits specific absorbance of hemicelluloses at 1380, 1168, 1050, and 900 cm −1 . In addition, we found that C. tropicalis can ferment the resulting corncob hemicellulosic hydrolysate with pH adjustment and activated charcoal treatment leading to a high xylitol yield and productivity of 0.77 g/g and 2.45 g/(L h), respectively.
研究领域:
生物化学
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发酵工程
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BIORESOURCE TECHNOLOGY
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2026
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IF 8.2
Xiaoying Gui,Jiaxuan Ji,Shuxian Hu,Xiyun Zhang,Yufeng Dong,Chenyang Wu,Yuanyuan Xia,Haiquan Yang,Wei Shen,Yu Cao,Li Zhou,Xianzhong Chen
Candida tropicalis was engineered as a novel chassis for efficient de novo astaxanthin production. • Promoter engineering balances CrtW / CrtZ to optimize metabolic flux toward astaxanthin. • Multiplex subcellular compartmentalization enhances astaxanthin biosynthesis. • ER expansion and lipid droplet engineering synergistically enhance product storage. • Fermentation optimization (additives, temperature) boosts astaxanthin production efficiency. Astaxanthin, a red ketocarotenoid, exhibits strong antioxidant, anti-inflammatory, pigmentation, and immunomodulatory activities. In this study, a high-β-carotene-producing Candida tropicalis strain was engineered for efficient astaxanthin biosynthesis using multiplex engineering strategies. First, promoter engineering was applied to balance the expression of β-carotene ketolase and hydroxylase, and an optimized promoter combination was identified, leading to an astaxanthin titer of 126.7 mg/L. Subsequently, subcellular compartmentalization was implemented by targeting the key enzymes to the cytosol, peroxisomes, and lipid droplets, followed by co-expression across multiple compartments, which raised the astaxanthin titer to 192.0 mg/L. Further enhancement was achieved through endoplasmic reticulum engineering to expand membrane-associated enzyme capacity and lipid engineering to improve product storage, increasing astaxanthin production to 249.8 mg/L. Finally, fermentation optimization significantly improved the shake-flask performance, yielding 320.1 mg/L astaxanthin. In a 5-L bioreactor, the astaxanthin titer reached 3096.2 mg/L, comparable to the highest reported production to date. This work represents the first efficient biosynthesis of astaxanthin in C. tropicalis and provides a novel chassis and technical framework for the industrial production of astaxanthin. Download: Download high-res image (46KB) Download: Download full-size image
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CHINESE CHEMICAL LETTERS
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2026
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IF 9.5
Xiaoming Zou,Hailin Zhang,Jianzhong Zeng,Ligui Wu,Ziyun Yin,Yimei Zeng,Qunyan Zhou,Lingling Rong,Yanbo Zhou,Xubiao Luo
The extensive use of gibberellic acid (GA 3 ) in agriculture leads to residues in agricultural products, raising potential human health concerns, particularly where residue limits are not established. Microbial degradation offers a promising remediation strategy, yet progress is limited by the scarcity of highly efficient degraders and an incomplete understanding of underlying mechanisms. Here, we identify a Candida tropicalis strain (GAJ-2) that achieves 83.63 % GA 3 removal within 120 h, exceeding the efficiencies reported for previously described GA 3 -degrading strains such as Aspergillus niger and Enterococcus mundtii (55.58 %–56.90 % within 5–7 days), and we further validate its residue-removal capacity in representative fruits and vegetables. Mechanistic analyses indicate that viable-cell-mediated GA 3 biotransformation by GAJ-2 mainly involves dehydroxylation, decarboxylation, and cleavage of the tetracyclic diterpenoid scaffold. These transformations are rationalized by the electronic distribution of oxygen-bearing functional groups and the electrophilic nature of C11 and adjacent positions in GA 3 . Multi-omics analyses further reveal enhanced energy metabolism and catalytic functions, together with efflux-pump regulation, and show a strong association between GA 3 catabolism and the upregulation of key enzymes ( e.g. , decarboxylases and dehydrogenases). Docking-based interaction profiling suggests that GA 3 associates with key proteins primarily through noncovalent interactions, including hydrogen bonding, van der Waals contacts, and electrostatic effects. Collectively, this work provides multi-level experimental and computational evidence supporting a plausible framework for GA 3 biodegradation by GAJ-2 and informs improved strategies for GA 3 pollution control.
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CARBOHYDRATE POLYMERS
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2024
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IF 10.7
Yangyang Liu,Ruilian Li,Yuchen Zhang,Siming Jiao,Tong Xu,Yuhang Zhou,Yujing Wang,Jinhua Wei,Wei Du,Morihisa Fujita,Yuguang Du,Zhuo A. Wang
Chitosan and chitooligosaccharide (COS) are renowned for their potent antimicrobial prowess, yet the precise antimicrobial efficacy of COS remains elusive due to scant structural information about the utilized saccharides. This study delves into the antimicrobial potential of COS, spotlighting a distinct hetero-chitooligosaccharide dubbed DACOS. In contrast to other COS, DACOS remarkably fosters the growth of Candida tropicalis planktonic cells and fungal biofilms. Employing gradient alcohol precipitation, DACOS was fractionated, unveiling diverse structural characteristics and differential impacts on C. tropicalis . Notably, in a murine model of systemic candidiasis, DACOS, particularly its 70 % alcohol precipitates, manifests a promotive effect on Candida infection. This research unveils a new pathway for exploring the intricate nexus between the structural attributes of chitosan oligosaccharides and their physiological repercussions, underscoring the imperative of crafting chitosan and COS with meticulously defined structural configurations.
研究领域:
微生物学
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药学
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分子生物学
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PubMed
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BRAZILIAN JOURNAL OF MICROBIOLOGY
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2025
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IF 1.9
Lv Jianhua,Gu Xiangnan,Hui Minmin,Luo Yingjie,Luo Wenbo,Zhao Huiting,Yin Shuqin,Feng Yan,Xue Zhiquan
Phenol hydroxylase (PH) plays a central role in phenol biodegradation pathways. In this study, the enzymatic activity of PH in Candida tropicalis GY8 was evaluated following phenol-induced cultivation, and oxidation products were analyzed via high-performance liquid chromatography (HPLC). Two phenol hydroxylase genes, CtPHE1 and CtPHE2 , were identified, and their expression patterns were examined using RT-qPCR. Functional analysis of the corresponding proteins was conducted by cloning and expressing the genes in Escherichia coli BL21(DE3). Enzymatic activity reached its maximum after 15 h of cultivation ( p < 0.01), and phenol conversion to catechol was verified by HPLC. RT-qPCR results indicated peak transcript levels at 10 h, with CtPHE2 showing consistently higher expression than CtPHE1 at 5, 10, and 15 h ( p < 0.01). Both recombinant proteins were capable of phenol degradation, with CtPHE2 exhibiting greater catalytic activity. These findings provide essential molecular information for advancing the understanding of phenol biodegradation mechanisms.
研究领域:
微生物学
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分子生物学
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环境科学
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ACS Synthetic Biology
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2026
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IF 3.9
Haiquan Yang,Lingling Chen,Wei Shen,Yuanyuan Xia,Li Zhou,Xianzhong Chen
(−)-α-bisabolol, a valuable sesquiterpene with anti-inflammatory and antibacterial properties, was sustainably produced via de novo high-titer biosynthesis in Candida tropicalis using engineered cell factories. To minimize resource-intensive extraction methods, we employed green metabolic engineering strategies, including an optimized Scaffold-Mediated Assembly Regulation Tool for coexpressing MrBBS and ERG20 genes, enhancing (−)-α-bisabolol titer 3.24-fold over the control strain. A novel Linker- and Scaffold-Mediated Assembly Regulation Tool further improved pathway efficiency by coordinating eight key acetyl-CoA/mevalonate pathway genes, achieving a 5.23-fold increase. Sustainable strain optimization included knockout of the competing gene DPP1 (yielding 261.2 mg•L–1) and the peroxisomal surface display of Cat2 and ERG10 (290.1 mg•L–1). Additional deletions of genes ADH1 and GPD1 reduced metabolic waste, boosting the titer 2.46-fold. A low-energy two-stage temperature control strategy further improved the titer to 1108.2 mg•L–1, while fed-batch fermentation in a 5 L fermenter─optimized for minimal energy and substrate input─achieved a record titer of 36.9 g•L–1. This study demonstrated a green, scalable biosynthesis platform for (−)-α-bisabolol, reducing reliance on petrochemical or plant-extraction routes, and provided a sustainable blueprint for terpenoid production in nonconventional yeasts.
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CHEMOSPHERE
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2022
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IF 8.943
Yuzhe He,Zhangna Wang,Tianyu Li,Xingxing Peng,Yetao Tang,Xiaoshan Jia
Candida tropicalis sp. was isolated with predominant biodegradation capability to phenol compounds, even with high concentration or in acid environment. The biodegradation of phenol was evaluated at the following concentrations 10–1750 mg L −1 , the strain exhibited well biodegradation efficiency. The maximum specific growth rate was 0.660 h −1 and the specific biodegradation rates was 0.47 mg (phenol) [(mg (VSS) h] −1 . Differentially expressed genes were screened out, and results revealed a complete process of energy and carbon metabolism. The genes’ arrangements and phylogenetic information showed the unique genetic characteristics of the strain. Catabolic pathways were reconstructed and some key phenol-degrading genes were obviously upregulated, including pheA , catA , OXCT and fadA . A notable detail that CMBL encoding carboxymethylenebutenolidase was speculated to be involved in a shortened pathway of phenol biodegradation, thereby contributing to the reconstruction of the novel phenol catabolic pathway through the hydrolases of dienelactone. Finally, key enzymes were verified by the analysis of specific activity.
研究领域:
环境微生物学
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分子生物学
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基因组学
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INDUSTRIAL CROPS AND PRODUCTS
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2026
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IF 6.4
Ge Zhang,Qiuxuan Xie,Jianhua Qiu,Ning Qian,Mengmeng Liu,Dong Li,Wei Ding,Qingyuan Hu,Bangzhu Peng,Kuo Huang,Changwen Ye
Candida tropicalis 2–17 effectively inhibits cigar tobacco molds via VOCs. • Fumigation reduced natural mold incidence from 94.98% to 28.27%. • Phenylacetaldehyde showed strong antifungal activity (MIC = 0.03 µL/mL). • Phenethyl alcohol and isoamyl alcohol exhibited synergistic antifungal effects. • Bio-fumigation improved flavor profiles without altering main chemical components. Postharvest mold severely threatens the economic value and sensory quality of cigar tobacco, a highly valuable, non-food industrial crop. Traditional direct-contact fungicides often disrupt the microecological and aroma profiles of the leaves. To address this issue, the present study establishes a novel, non-contact bio-fumigation strategy using Candida tropicalis 2–17 to control mold without leaving physical or chemical residues. In vitro assays demonstrated that volatile organic compounds (VOCs) emitted by strain 2–17 significantly inhibited all eight tested molds, achieving a 100% inhibition rate against six of them. Mechanistically, headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS–SPME–GC–MS) identified eight major VOCs, predominantly alcohols and esters. Among these, phenylacetaldehyde exhibited an extremely low minimum inhibitory concentration (MIC) of 0.03 µL/mL against Aspergillus montevidensis , while a distinct synergistic inhibitory effect (FIC = 0.375) was identified between phenethyl alcohol and isoamyl alcohol . Furthermore, in situ validations revealed that 2–17 fumigation reduced the natural mold incidence from 94.98% to 28.27%. Flavoromic and chemical analyses confirmed that this gas–phase treatment preserved the core chemical components of the leaves ( P > 0.05) while favorably modulating specific volatile profiles, such as downregulating the off-flavor (Z/E)-3-Nonen-1-ol (log 2 FC = –4.295) and upregulating D/ L -Fenchone (log 2 FC = +4.710). These findings demonstrate that C. tropicalis 2–17 is a promising biocontrol agent, providing a quality–preserving green technology for the postharvest storage of densely stacked industrial crops. Download: Download high-res image (226KB) Download: Download full-size image
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