1.Discovery and functional verification of endogenous glucanases for scleroglucan hydrolysis in Sclerotium rolfsii.
Weizhu ZENG ; Runqing TAN ; Jingwen ZHOU
Chinese Journal of Biotechnology 2021;37(1):207-217
Scleroglucan is a high-molecular water-soluble microbial exopolysaccharide and mainly applied in the fields of petroleum, food, medicine and cosmetics. The high molecular weight of scleroglucan produced by microbial fermentation leads to low solubility, high viscosity and poor dispersibility, thus bringing a series of difficulties to extraction, preservation and application. It is important to explore suitable degradation method to adjust the molecular weight of scleroglucan for expanding its industrial application. Taking Sclerotium rolfsii WSH-G01 as a model strain, in which functional annotations of the glucanase genes were conducted by whole genome sequencing. Based on design of culture system for culture system for differential expression of β-glucanase, endogenous β-glucanase genes in S. rolfsii WSH-G01 were excavated by transcriptomics analysis. Functions of these potential hydrolases were further verified. Finally, 14 potential endogenous hydrolase genes were obtained from S. rolfsii. After heterologous overexpression in Pichia pastoris, 10 soluble enzymes were obtained and 5 of them had the activity of laminarin hydrolysis by SDS-PAGE and enzyme activity analysis. Further investigation of the 5 endogenous hydrolases on scleroglucan degradation showed that enzyme GME9860 has positive hydrolysis effect. The obtained results provide references not only for obtaining low and medium molecular weight of scleroglucan with enzymatic hydrolysis, but also for producing different molecular weight of scleroglucan during S. rolfsii fermentation process with metabolic engineering.
Basidiomycota/genetics*
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Glucans
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Hydrolysis
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Saccharomycetales
2.Status quo of and challenges for research on rust disease in medicinal plants.
Zhong-Lian YU ; Juan YANG ; Mei-Yan LEI ; Jian QUAN ; Tian-Jian YANG ; Cheng-Qian YANG
China Journal of Chinese Materia Medica 2021;46(14):3566-3576
Medicinal plants are beneficial to human health. However,most of the major producing regions of medicinal plants suffer from rust disease,which threatens the yield and quality of Chinese medicinal materials,thus causes huge economic loss,and hinders the sustainable development of the Chinese medicine industry. By the end of 2020,rust disease had been reported in medicinal plants of 76 species and 33 families. In the 76 species,79 rust pathogens were detected. The majority of these pathogens belonged to Puccinia( 33,39. 24%),Coleosporium( 14,15. 19%),and Aecidium( 11,13. 92%). Of these 79 rust pathogens,10 were autoecious and 13 were heteroecious. Through literature research,this study reviewed the symptoms,pathogen species,severity and distribution,prevalence and occurrence conditions,and control measures of rust disease in medicinal plants,and thereby summarized the research status of rust disease in medicinal plants and the gap with other plants,which is expected to serve as a reference for further research on rust disease in medicinal plants.
Basidiomycota/genetics*
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Humans
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Plant Diseases
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Plants, Medicinal
3.Advances in the phylogenesis of Agaricales and its higher ranks and strategies for establishing phylogenetic hypotheses.
Rui-Lin ZHAO ; Dennis E DESJARDIN ; Kasem SOYTONG ; Kevin D HYDE
Journal of Zhejiang University. Science. B 2008;9(10):779-786
We present an overview of previous research results on the molecular phylogenetic analyses in Agaricales and its higher ranks (Agaricomycetes/Agaricomycotina/Basidiomycota) along with the most recent treatments of taxonomic systems in these taxa. Establishing phylogenetic hypotheses using DNA sequences, from which an understanding of the natural evolutionary relationships amongst clades may be derived, requires a robust dataset. It has been recognized that single-gene phylogenies may not truly represent organismal phylogenies, but the concordant phylogenetic genealogies from multiple-gene datasets can resolve this problem. The genes commonly used in mushroom phylogenetic research are summarized.
Agaricales
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classification
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genetics
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Basidiomycota
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classification
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genetics
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DNA, Fungal
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genetics
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Evolution, Molecular
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Models, Genetic
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Phylogeny
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Species Specificity
4.Mrakia psychrophila sp. nov., a new species isolated from Antarctic soil.
Journal of Zhejiang University. Science. B 2007;8(4):260-265
The yeast strain (Y18) was isolated from a soil sample collected from Fildes Peninsula, Antarctica. The strain is a psychrophilic yeast with optimum and maximum growth temperatures of 10 degrees C and 18 degrees C, respectively. Teliospores were formed after 7 d on malt agar, when the germination of teliospores was observed. Both inositol and D-glucuronate were assimilated. Positive results of the DBB (diazonium blue B) color reaction, urease test, and starch formation were observed. The major CoQ is Q(8). All results indicated that Y18 belongs to the genes of Mrakia. The 18S rDNA sequence analyses showed that Y18 is closely related to Mrakia frigida. DNA-DNA relatedness study, and some biochemistry characteristics indicated that Y18 represents a new species for which Mrakia psychrophila sp. nov. is proposed.
Antarctic Regions
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Basidiomycota
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classification
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genetics
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China
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DNA, Fungal
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genetics
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Phylogeny
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Soil Microbiology
5.Repeated batch and fed-batch process for astaxanthin production by Phaffia rhodozyma.
Anfeng XIAO ; Hui NI ; Lijun LI ; Huinong CAI
Chinese Journal of Biotechnology 2011;27(4):598-605
A comparative study of batch and repeated batch process was carried out for astaxanthin fermentation of Phaffia rhodozyma to develop a more economical method for astaxanthin industrial production. In shaking flask fermentation, the change of biomass and astaxanthin production was studied to compare the five-day cycle with four-day cycle of repeated batch culture of P. rhodozyma. Astaxanthin production increased at first and then decreased subsequently in seven cycles, yet the yield of astaxanthin in the next six cycles remains higher than that of the first cycle. Comparing the average production of astaxanthin in the seven cycles, four-day cycle performed even better than five-day cycle. Subsequently, a repeated fed-batch process was used in a 5-1 bioreactor. The experimental data showed that biomass and astaxanthin production of the second batch could reach the level of the first batch, no matter that the carbon source was glucose or hydrolysis sugar of starch. This result showed that this strain had good stability, and thus repeated batch and fed-batch process could be applied in astaxanthin fermentation for economical purpose.
Basidiomycota
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genetics
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metabolism
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Batch Cell Culture Techniques
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methods
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Bioreactors
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microbiology
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Fermentation
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Industrial Microbiology
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methods
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Xanthophylls
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biosynthesis
6.Genome-wide identification and expression analysis of CSLA gene family of Dendrobium catenatum.
Ya-Qian GAO ; Xue-Liang CHEN ; Dong-Hong CHEN ; Jing-Jing LIU ; Jin-Ping SI
China Journal of Chinese Materia Medica 2020;45(13):3120-3127
Glucomannan is the key active ingredient of Dendrobium catenatum, and CSLA family is responsible for glucomannan biosynthesis. In order to systematically evaluate the CSLA family members of D. catenatum, the bioinformatics methods were performed for genome-wide identification of DcCSLA gene family members through the genomic data of D. catenatum downloaded from the NCBI database, and further analyses of their phylogenetic relationship, gene structure, protein conserved domains and motifs, promoter cis-elements and gene expression profiles in response to stresses. The results showed that D. catenatum contains 13 CSLA members, all of which contain 9-10 exons. In the evolutionary relationship, CSLA genes were clustered into 5 groups, DcCSLA genes were distributed in all branches. Among which the ancestral genes of groupI existed before the monocot-dicot divergence, and groupⅡ-Ⅴ only existed in the monocot plants, indicating that group Ⅰ represents the earliest origin group. CSLA proteins are characteristic of the signature CESA_CaSu_A2 domain. Their promoter regions contain cis elements related to stresses and hormones. Under different stress treatments, low temperature induces the expression of DcCSLA5 and inhibits the expression of DcCSLA3. Infection of Sclerotium delphinii inhibits DcCSLA3/4/6/8/9/10 expression. Under the treatment of jasmonic acid, DcCSLA11 expression was significantly up-regulated, and DcCSLA2/5/7/12/13 were significantly down-regulated. These results laid a foundation for further study on the function of DcCSLA genes in glucomannan biosynthesis and accumulation.
Basidiomycota
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Cold Temperature
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Dendrobium
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genetics
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Gene Expression Regulation, Plant
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Genome, Plant
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Multigene Family
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Phylogeny
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Plant Proteins
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genetics
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Stress, Physiological
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Transcriptome
7.Production of β-carotene by metabolically engineered Saccharomyces cerevisiae.
Beibei WANG ; Mingyu SHI ; Dong WANG ; Jiaoyang XU ; Yi LIU ; Hongjiang YANG ; Zhubo DAI ; Xueli ZHANG
Chinese Journal of Biotechnology 2014;30(8):1204-1216
β-carotene has a wide range of application in food, pharmaceutical and cosmetic industries. For microbial production of β-carotene in Saccharomyces cerevisiae, the supply of geranylgeranyl diphosphate (GGPP) was firstly increased in S. cerevisiae BY4742 to obtain strain BY4742-T2 through over-expressing truncated 3-hydroxy-3-methylglutaryl-CoA reductase (tHMGR), which is the major rate-limiting enzyme in the mevalonate (MVA) pathway, and GGPP synthase (GGPS), which is a key enzyme in the diterpenoid synthetic pathway. The β-carotene synthetic genes of Pantoea agglomerans and Xanthophyllomyces dendrorhous were further integrated into strain BY4742-T2 for comparing β-carotene production. Over-expression of tHMGR and GGPS genes led to 26.0-fold increase of β-carotene production. In addition, genes from X. dendrorhous was more efficient than those from P. agglomerans for β-carotene production in S. cerevisiae. Strain BW02 was obtained which produced 1.56 mg/g (dry cell weight) β-carotene, which could be used further for constructing cell factories for β-carotene production.
Basidiomycota
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enzymology
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Farnesyltranstransferase
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genetics
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metabolism
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Hydroxymethylglutaryl CoA Reductases
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genetics
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metabolism
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Metabolic Engineering
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Polyisoprenyl Phosphates
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Saccharomyces cerevisiae
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metabolism
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beta Carotene
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biosynthesis
8.Genetic analysis and SSR mapping on an new stem stripe rust resistance gene YrY206 in Aegilops tauschii.
Haiquan ZHANG ; Jie LANG ; Shuqin MA ; Baoshi ZHANG
Chinese Journal of Biotechnology 2008;24(8):1475-1479
A wheat stripe rust resistance gene was screened out from Aegilops tauschii which is relative genera of wheat species, broadening the genetic basis of the anti-disease character of wheat species. By hybridizing diversed Ae. Tauschii species, which is either resistant or susceptible to wheat stripe rust, a dominant wheat stripe rust resistance gene was detected from Ae. Tauschii (Coss.) Schmal Y206. The novel gene was temporarily designated as YrY206. By bulk segregation analysis, four microsatellite markers Wmc11a, Xgwm71c, Xgwm161 and Xgwm183 were found to be linked to YrY206 with genetic distances of 4.0, 3.3, 1.5 and 9.3 cM, respectively. According to the locations of the linked markers, the resistance gene was located on chromosome 3DS. Based on the chromosomal location and the resistance pattern of the gene, YrY206 should be a novel stripe rust resistance gene.
Basidiomycota
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pathogenicity
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Chromosome Mapping
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Immunity, Innate
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genetics
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Microsatellite Repeats
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genetics
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Plant Diseases
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genetics
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microbiology
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Plant Proteins
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genetics
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Poaceae
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genetics
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microbiology
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Triticum
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genetics
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microbiology
9.Expression, purification and characterization of a novel fatty acid synthase from Rhodosporidium toruloides.
Zhiwei ZHU ; Sufang ZHANG ; Xinping LIN ; Wujun LIU ; Zongbao K ZHAO
Chinese Journal of Biotechnology 2014;30(9):1414-1423
Fatty acid synthase (FAS) catalyses the reaction between acetyl-CoA and malonyl-CoA to produce fatty acids. It is one of the most important enzyme in lipid biosynthesis. FAS of the oleaginous yeast Rhodosporidium toruloides has two acyl carrier protein (ACP) domains and a distinct subunit composition compared with FASs of other species. As ACP is a protein cofactor crucial for fatty acid chain elongation, more ACPs in the FAS may facilitate the reaction. To study the biochemical and structural properties of this novel FAS from R. toruloides, plasmids were constructed and transformed into Escherichia coli BL21 (DE3). The strain ZWE06 harboring plasmids pET22b-FAS1 and pET24b-FAS2 could co-overexpress the two subunits. The recombinant FAS was purified by sequentially using ammonium sulphate precipitation, sucrose density gradient centrifugation and anion exchange chromatography. The specific activity of the recombinant FAS was 548 mU/mg. The purified complex would be used to study enzyme kinetics and protein structure of FAS, and heterogeneous expression and purification will facilitate revealing the mechanism of this novel FAS with double ACPs.
Acyl Carrier Protein
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Basidiomycota
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enzymology
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Chromatography
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Escherichia coli
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metabolism
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Fatty Acid Synthases
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biosynthesis
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genetics
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Fatty Acids
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biosynthesis
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Plasmids
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Recombinant Proteins
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biosynthesis
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genetics
10.Characterization and evaluation of an astaxanthin over-producing Phaffia rhodozyma.
Hui NI ; Qinglin HONG ; Anfeng XIAO ; Lijun LI ; Huinong CAI ; Wenjin SU
Chinese Journal of Biotechnology 2011;27(7):1065-1075
We evaluated an astaxanthin overproducing Phaffia rhodozyma JMU-MVP14, and developed astaxanthin high-yielding fermentation process. We analyzed several fermentation parameters, i.e., biomass, astaxanthin and total carotenoids content to compare the characteristics of P rhodozyma JMU-MVP14 and the original strain through flask fermentation experiments. We conducted batch and fed-batch fermentation experiments in 7 L fermentor to investigate the effects of pH controlling models and feeding medium compositions on the production of astaxanthin. We further evaluated the capability and practical value of P rhodozyma JMU-MVP14 by fed-batch cultivation in the 1 m3 fermentor. Flask fermentation experiments revealed that P. rhodozyma JMU-MVP14 produced high yield of astaxanthin and carotenoids with specific productivity of astaxanthin and specific productivity of total carotenoids of 6.01 mg/g and 10.38 mg/g. Results of batch culture experiments in the 7 L fermentor showed that controlling the pH by ammonia auto-feeding was better than discontinuously adjusting pH value at 6.0 with regard to the high productivities of biomasses and astaxanthin. This P. rhodozyma strain synthesized astaxanthin partially linked to the growth with the Ks and pmax of 0.20 h ' and 21.73 g/L, respectively. Results of batch-fed fermentations in 7 L fermentor indicated that the complex feeding medium consisted of 50% glucose, 0.5% yeast extract and 0.3% corn steep syrup had lower astaxanthin productivity than the simple feeding medium containing only 50% glucose, which produced biomass, volumetric productivity of astaxanthin, volumetric productivity of total carotenoids, specific productivity of astaxanthin and total carotenoids at 32.81 g/L, 155.99 mg/L, 4.94 mg/g, 399.99 mg/L and 12.19 mg/g, respectively. As fed-batch cultured in 1 m3 fermentor, P rhodozyma JMU-MVP14 yielded 85.11 g/L of biomass, 279.96 mg/L of volumetric productivity of astaxanthin, 618.01 mg/L of volumetric productivity of total carotenoids, 3.29 mg/g of specific productivity of astaxanthin and 7.26 mg/g of specific productivity of total carotenoids. Additionally, P rhodozyma JMU-MVP14 cell contained 21.54% of protein, 41.34% of carbohydrate and 34.31% of lipid. These comprehensive results suggest that P. rhodozyma JMU-MVPl14 has great practical prosperity related to its strong ability to produce astaxanthin and good value byproducts.
Basidiomycota
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genetics
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growth & development
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metabolism
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Batch Cell Culture Techniques
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Carotenoids
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biosynthesis
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Culture Media
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Fermentation
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Hydrogen-Ion Concentration
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Industrial Microbiology
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Kinetics
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Xanthophylls
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biosynthesis