The use of organoids in creating immune microenvironments and treating gynecological tumors.

Owing to patient-derived tumor tissues and cells, significant advances have been made in personalized cancer treatment and precision medicine, with cancer stem cell-derived three-dimensional tumor organoids serving as crucial in vitro models that accurately replicate the structural, phenotypic, and genetic characteristics of tumors. However, despite their extensive use in drug testing, genome editing, and transplantation for facilitating personalized treatment approaches in clinical practice, the inadequate capacity of these organoids to effectively model immune cells and stromal components within the tumor microenvironment limits their potential. Additionally, effective clinical immunotherapy has led the tumor immune microenvironment to garner considerable attention, increasing the demand for simulating patient-specific tumor-immune interactions. Consequently, co-culture techniques integrating tumor organoids with immune cells and tumor microenvironment constituents have been developed to expand the possibilities for personalized drug response investigations, with recent advancements enhancing the understanding of the strengths, limitations, and applicability of the co-culture approach. Herein, the recent advancements in the field of tumor organoids have been comprehensively reviewed, specifically highlighting the tumor organoid co-culture-related developments with various immune cell models and their implications for clinical research. Furthermore, this review delineates the current state of research and application of organoid models regarding the therapeutic approaches and related challenges for gynecological tumors. This study may provide a theoretical basis for further research on the use of patient-derived organoids in tumor immunity, drug development, and precision medicine.

UV mutagenesis improves growth potential of green algae in a green algae-yeast co-culture system.

It is known that co-cultivation of green algae with heterotrophic microorganisms, such as yeast, improves green algae's growth potential and carbon dioxide fixation, even under low CO2 concentration conditions such as the atmosphere. Introducing mutations into green algae is also expected to enhance their growth potential. In this study, we sought to improve the growth potential of a co-culture system of the green algae Chlamydomonas reinhardtii and the yeast Saccharomyces cerevisiae by introducing mutations into the green algae. Additionally, we performed a transcriptome analysis of the co-culture of the green algae mutant strain with yeast, discussing the interaction between the green algae mutant strain and the yeast. When the green algae mutant strain was co-cultured with yeast, the number of green algae cells reached 152 × 105 cells/mL after 7 days of culture. This count was 2.6 times higher than when the wild-type green algae strain was cultured alone and 1.6 times higher than when the wild-type green algae strain and yeast were co-cultured. The transcriptome analysis also indicated that the primary reason for the increased growth potential of the green algae mutant strain was its enhanced photosynthetic activity and nitrogen utilization efficiency.

Improvement of cell growth in green algae Chlamydomonas reinhardtii through co-cultivation with yeast Saccharomyces cerevisiae.

PURPOSE: CO2 fixation methods using green algae have attracted considerable attention because they can be applied for the fixation of dilute CO2 in the atmosphere. However, green algae generally exhibit low CO2 fixation efficiency under atmospheric conditions. Therefore, it is a challenge to improve the CO2 fixation efficiency of green algae under atmospheric conditions. Co-cultivation of certain microalgae with heterotrophic microorganisms can increase the growth potential of microalgae under atmospheric conditions. The objective of this study was to determine the culture conditions under which the growth potential of green algae Chlamydomonas reinhardtii is enhanced by co-culturing with the yeast Saccharomyces cerevisiae, and to identify the cause of the enhanced growth potential. RESULTS: When C. reinhardtii and S. cerevisiae were co-cultured with an initial green algae to yeast inoculum ratio of 1:3, the cell concentration of C. reinhardtii reached 133 × 105 cells/mL on day 18 of culture, which was 1.5 times higher than that of the monoculture. Transcriptome analysis revealed that the expression levels of 363 green algae and 815 yeast genes were altered through co-cultivation. These included genes responsible for ammonium transport and CO2 enrichment mechanism in green algae and the genes responsible for glycolysis and stress responses in yeast. CONCLUSION: We successfully increased C. reinhardtii growth potential by co-culturing it with S. cerevisiae. The main reasons for this are likely to be an increase in inorganic nitrogen available to green algae via yeast metabolism and an increase in energy available for green algae growth instead of CO2 enrichment.

Enhancing extracellular monascus pigment production in submerged fermentation with engineered microbial consortia.

In this study, we investigated the impact of microbial interactions on Monascus pigment (MP) production. We established diverse microbial consortia involving Monascus purpureus and Lactobacillus fermentum. The addition of Lactobacillus fermentum (4% at 48 h) to the submerged fermentation of M. purpureus resulted in a significantly higher MP production compared to that achieved using the single-fermentation system. Co-cultivation with immobilized L. fermentum led to a remarkable increase of 59.18% in extracellular MP production, while mixed fermentation with free L. fermentum caused a significant decrease of 66.93% in intracellular MPs, contrasting with a marginal increase of 4.52% observed during co-cultivation with immobilized L. fermentum and the control group respectively. The findings indicate an evident enhancement in cell membrane permeability of M. purpureus when co-cultivated with immobilized L. fementum. Moreover, integrated transcriptomic and metabolomic analyses were conducted to elucidate the regulatory mechanisms underlying MP biosynthesis and secretion following inoculation with immobilized L. fementum, with specific emphasis on glycolysis, steroid biosynthesis, fatty acid biosynthesis, and energy metabolism.

The Impact of the Culture Regime on the Metabolome and Anti-Phytopathogenic Activity of Marine Fungal Co-Cultures.

Co-cultivation, coupled with the OSMAC approach, is considered an efficient method for expanding microbial chemical diversity through the activation of cryptic biosynthetic gene clusters (BGCs). As part of our project aiming to discover new fungal metabolites for crop protection, we previously reported five polyketides, the macrolides dendrodolides E (1) and N (2), the azaphilones spiciferinone (3) and 8α-hydroxy-spiciferinone (4), and the bis-naphtho-γ-pyrone cephalochromin (5) from the solid Potato Dextrose Agar (PDA) co-culture of two marine sediment-derived fungi, Plenodomus influorescens and Pyrenochaeta nobilis. However, some of the purified metabolites could not be tested due to their minute quantities. Here we cultivated these fungi (both axenic and co-cultures) in liquid regime using three different media, Potato Dextrose Broth (PDB), Sabouraud Dextrose Broth (SDB), and Czapek-Dox Broth (CDB), with or without shaking. The aim was to determine the most ideal co-cultivation conditions to enhance the titers of the previously isolated compounds and to produce extracts with stronger anti-phytopathogenic activity as a basis for future upscaled fermentation. Comparative metabolomics by UPLC-MS/MS-based molecular networking and manual dereplication was employed for chemical profiling and compound annotations. Liquid co-cultivation in PDB under shaking led to the strongest activity against the phytopathogen Phytophthora infestans. Except for compound 1, all target compounds were detected in the co-culture in PDB. Compounds 2 and 5 were produced in lower titers, whereas the azaphilones (3 and 4) were overexpressed in PDB compared to PDA. Notably, liquid PDB co-cultures contained meroterpenoids and depside clusters that were absent in the solid PDA co-cultures. This study demonstrates the importance of culture regime in BGC regulation and chemical diversity of fungal strains in co-culture studies.

Co-culturing Bifidobacterium animalis ssp. lactis with Lactobacillus helveticus accelerates its growth and fermentation in milk through metabolic interactions.

[Objective] This study aimed to investigate the interaction between Lactobacillus helveticus H9 (H9) and Bifidobacterium animalis ssp. lactis Probio-M8 (M8) through metabolomics analysis, focusing on understanding how co-culturing these strains can enhance bacterial growth and metabolism, thereby shortening the fermentation cycle and improving efficiency. [Methods] The H9 and M8 strains were cultured individually and in combination (1:1 ratio) in milk. The fermented milk metabolomes were analyzed using solid-phase microextraction-gas chromatography-mass spectrometry. [Results] In the dual-strain fermentation, the M8 strain exhibited a 2.33-fold increase in viable bacterial count compared with single-strain fermentation. Additionally, the dual-strain fermentation resulted in greater metabolite abundance and diversity. Notably, the dual-strain fermented milk showed significantly elevated levels of metabolites, including 5-methyl-2-hexanone, (E)-3-octen-2-one, acetic acid, alanine, and 3-hydroxy-butanal. [Conclusion] Our results demonstrated that co-culturing the M8 and H9 strains accelerated growth and fermentation efficiency. This enhancement effect is likely attributed to the strong proteolytic ability of the H9 strain, which hydrolyzes casein to produce small molecular peptides, alanine, tyrosine, and other growth-promoting factors. The insights gained from this study have significant implications for probiotics and the dairy industry, potentially leading to shorter fermentation cycles, enhanced cost-effectiveness, and improved nutritional and functional properties of future fermented milk products. Additionally, these findings may contribute to advancements in probiotic research and applications.

Bacillus sp. G2112 Detoxifies Phenazine-1-carboxylic Acid by N5 Glucosylation.

Microbial symbionts of plants constitute promising sources of biocontrol organisms to fight plant pathogens. Bacillus sp. G2112 and Pseudomonas sp. G124 isolated from cucumber (Cucumis sativus) leaves inhibited the plant pathogens Erwinia and Fusarium. When Bacillus sp. G2112 and Pseudomonas sp. G124 were co-cultivated, a red halo appeared around Bacillus sp. G2112 colonies. Metabolite profiling using liquid chromatography coupled to UV and mass spectrometry revealed that the antibiotic phenazine-1-carboxylic acid (PCA) released by Pseudomonas sp. G124 was transformed by Bacillus sp. G2112 to red pigments. In the presence of PCA (>40 µg/mL), Bacillus sp. G2112 could not grow. However, already-grown Bacillus sp. G2112 (OD600 > 1.0) survived PCA treatment, converting it to red pigments. These pigments were purified by reverse-phase chromatography, and identified by high-resolution mass spectrometry, NMR, and chemical degradation as unprecedented 5N-glucosylated phenazine derivatives: 7-imino-5N-(1'ß-D-glucopyranosyl)-5,7-dihydrophenazine-1-carboxylic acid and 3-imino-5N-(1'ß-D-glucopyranosyl)-3,5-dihydrophenazine-1-carboxylic acid. 3-imino-5N-(1'ß-D-glucopyranosyl)-3,5-dihydrophenazine-1-carboxylic acid did not inhibit Bacillus sp. G2112, proving that the observed modification constitutes a resistance mechanism. The coexistence of microorganisms-especially under natural/field conditions-calls for such adaptations, such as PCA inactivation, but these can weaken the potential of the producing organism against pathogens and should be considered during the development of biocontrol strategies.

Reasons and riddance of Agrobacterium tumefaciens overgrowth in plant transformation.

Agrobacterium tumefaciens-mediated plant transformation has become routine work across the world to study gene function and the production of genetically modified plants. However, several issues hamper the transformation process in a profound way, both directly and indirectly. One of the major concerns is the overgrowth of Agrobacterium, which occasionally appears after the co-cultivation phase of the explant. This phenomenon is reported in several species and seems to spoil the whole transformation process. There are multiple approaches being employed to counter this unwanted growth of bacteria in a few plant species. In reality, once the overgrowth appears, it becomes nearly impossible to cure it. Hence, for the prevention of this phenomenon, numerous factors are regulated. These factors are: explant nature, A. tumefaciens strain, T-DNA vector, co-cultivation (time and condition), acetosyringone, washing medium, antibiotics (type, concentration, combination, incubation period), etc. In this article, we discuss these factors based on available reports. It can be of immense help in formulating viable strategies to control A. tumefaciens overgrowth.

Metabolomics reveal metabolic variation caused by co-culture of Arthrobacter ureafaciens and Trichoderma harzianum and their impacts on wheat germination.

Arthrobacter ureafaciens DnL1-1 is a bacterium used for atrazine degradation, while Trichoderma harzianum LTR-2 is a widely used biocontrol fungus. In this study, a liquid co-cultivation of these two organisms was initially tested. The significant changes in the metabolome of fermentation liquors were investigated based on cultivation techniques (single-cultured and co-cultured DnL1-1 and LTR-2) using an UPLC-QTOF-MS in an untargeted metabolomic approach. Principle components analysis (PCA) and partial least squares discriminant analysis (PLS-DA) supervised modelling revealed modifications of the metabolic profiles in fermentation liquors as a function of interactions between different strains. Compared with pure-cultivation of DnL1-1, 51 compounds were altered during the cocultivation, with unique and significant differences in the abundance of organic nitrogen compounds (e.g. carnitine, acylcarnitine 4:0, acylcarnitine 5:0, 3-dehydroxycarnitine and O-acetyl-L-carnitine) and trans-zeatin riboside. Nevertheless, compared with pure-cultivation of LTR-2, the abundance of 157 compounds, including amino acids, soluble sugars, organic acids, indoles and derivatives, nucleosides, and others, changed significantly in the cocultivation. Among them, the concentration of tryptophan, which is a precursor to indoleacetic acid, indoleacetic acid, aspartic acid, and L-glutamic acid increased while that of most soluble sugars decreased upon cocultivation. The fermentation filtrates of co-cultivation of LTR-2 and DnL1-1 showed significant promoting effects on germination and radicle length of wheat. A subsequent experiment demonstrated synergistic effects of differential metabolites caused by co-cultivation of DnL1-1 and LTR-2 on wheat germination. Comprehensive metabolic profiling may provide valuable information on the effects of DnL1-1 and LTR-2 on wheat growth.

Microbial synthesis of the plant natural product precursor p-coumaric acid with Corynebacterium glutamicum.

BACKGROUND: Phenylpropanoids such as p-coumaric acid represent important precursors for the synthesis of a broad range of plant secondary metabolites including stilbenoids, flavonoids, and lignans, which are of pharmacological interest due to their health-promoting properties. Although extraction from plant material or chemical synthesis is possible, microbial synthesis of p-coumaric acid from glucose has the advantage of being less expensive and more resource efficient. In this study, Corynebacterium glutamicum was engineered for the production of the plant polyphenol precursor p-coumaric acid from glucose. RESULTS: Heterologous expression of the tyrosine ammonia-lyase encoding gene from Flavobacterium johnsoniae enabled the conversion of endogenously provided tyrosine to p-coumaric acid. Product consumption was avoided by abolishing essential reactions of the phenylpropanoid degradation pathway. Accumulation of anthranilate as a major byproduct was eliminated by reducing the activity of anthranilate synthase through targeted mutagenesis to avoid tryptophan auxotrophy. Subsequently, the carbon flux into the shikimate pathway was increased, phenylalanine biosynthesis was reduced, and phosphoenolpyruvate availability was improved to boost p-coumaric acid accumulation. A maximum titer of 661 mg/L p-coumaric acid (4 mM) in defined mineral medium was reached. Finally, the production strain was utilized in co-cultivations with a C. glutamicum strain previously engineered for the conversion of p-coumaric acid into the polyphenol resveratrol. These co-cultivations enabled the synthesis of 31.2 mg/L (0.14 mM) resveratrol from glucose without any p-coumaric acid supplementation. CONCLUSIONS: The utilization of a heterologous tyrosine ammonia-lyase in combination with optimization of the shikimate pathway enabled the efficient production of p-coumaric acid with C. glutamicum. Reducing the carbon flux into the phenylalanine and tryptophan branches was the key to success along with the introduction of feedback-resistant enzyme variants.

A review on microalgal-bacterial co-culture: The multifaceted role of beneficial bacteria towards enhancement of microalgal metabolite production.

Mass microalgal-bacterial co-cultures have come to the fore of applied physiological research, in particularly for the optimization of high-value metabolite from microalgae. These co-cultures rely on the existence of a phycosphere which harbors unique cross-kingdom associations that are a prerequisite for the cooperative interactions. However, detailed mechanisms underpinning the beneficial bacterial effects onto microalgal growth and metabolic production are rather limited at the moment. Hence, the main purpose of this review is to shed light on how bacteria fuels microalgal metabolism or vice versa during mutualistic interactions, building upon the phycosphere which is a hotspot for chemical exchange. Nutrients exchange and signal transduction between two not only increase the algal productivity, but also facilitate in the degradation of bio-products and elevate the host defense ability. Main chemical mediators such as photosynthetic oxygen, N-acyl-homoserine lactone, siderophore and vitamin B12 were identified to elucidate beneficial cascading effects from the bacteria towards microalgal metabolites. In terms of applications, the enhancement of soluble microalgal metabolites is often associated with bacteria-mediated cell autolysis while bacterial bio-flocculants can aid in microalgal biomass harvesting. In addition, this review goes in depth into the discussion on enzyme-based communication via metabolic engineering such as gene modification, cellular metabolic pathway fine-tuning, over expression of target enzymes, and diversion of flux toward key metabolites. Furthermore, possible challenges and recommendations aimed at stimulating microalgal metabolite production are outlined. As more evidence emerges regarding the multifaceted role of beneficial bacteria, it will be crucial to incorporate these findings into the development of algal biotechnology.

Formamide-based production of amines by metabolically engineering Corynebacterium glutamicum.

Formamide is rarely used as nitrogen source by microorganisms. Therefore, formamide and formamidase have been used as protection system to allow for growth under non-sterile conditions and for non-sterile production of acetoin, a product lacking nitrogen. Here, we equipped Corynebacterium glutamicum, a renowned workhorse for industrial amino acid production for 60 years, with formamidase from Helicobacter pylori 26695, enabling growth with formamide as sole nitrogen source. Thereupon, the formamide/formamidase system was exploited for efficient formamide-based production of the nitrogenous compounds L-glutamate, L-lysine, N-methylphenylalanine, and dipicolinic acid by transfer of the formamide/formamidase system to established producer strains. Stable isotope labeling verified the incorporation of nitrogen from formamide into biomass and the representative product L-lysine. Moreover, we showed ammonium leakage during formamidase-based access of formamide to be exploitable to support growth of formamidase-deficient C. glutamicum in co-cultivation and demonstrated that efficient utilization of formamide as sole nitrogen source benefitted from overexpression of formate dehydrogenase. KEY POINTS: • C. glutamicum was engineered to access formamide. • Formamide-based production of nitrogenous compounds was established. • Nitrogen cross-feeding supported growth of a formamidase-negative strain.

Microalgal conversion of whey and lactose containing substrates: current state and challenges.

Currently dairy processing by-products, such as whey, still propose a significant threat to the environment if unproperly disposed. Microalgal bioconversion of such lactose containing substrates can be used for production of valuable microalgae-derived bio-products as well as for significant reduction of environmental risks. Moreover, it could significantly reduce microalgae biomass production costs, being a significant obstacle in commercialization of many microalgae species. This review summarizes current knowledge on the use of lactose containing substrates, e.g. whey, for the production of value-added products by microalgae, including information on producer cultures, fermentation methods and cultivation conditions, bioprocess productivity and ability of microalgal cultures to produce ß-galactosidases. It can be stated, that despite several limitations lactose-containing substrates can be successfully used for both-the production of microalgal biomass and removal of high amounts of excess nutrients from the cultivation media. Moreover, co-cultivation of microalgae and other microorganisms can further increase the removal of nutrients and the production of biomass. Further investigations on lactose metabolism by microalgae, selection of suitable strains and optimisation of the cultivation process is required in order to enable large-scale microalgae production on these substrates.

Streptomyces sp. BV410: Interspecies cross-talk for staurosporine production.

AIMS: Sequencing and genome analysis of two co-isolated streptomycetes, named BV410-1 and BV410-10, and the effect of their co-cultivation on the staurosporine production. METHODS AND RESULTS: Identification of two strains through genome sequencing and their separation using different growth media was conducted. Sequence analysis revealed that the genome of BV410-1 was 9.5 Mb, whilst that of BV410-10 was 7.1 Mb. AntiSMASH analysis identified 28 biosynthetic gene clusters (BGCs) from BV410-1, including that responsible for staurosporine biosynthesis, whilst 20 BGCs were identified from BV410-10. The addition of cell-free supernatant from BV410-10 monoculture to BV410-1 fermentations improved the staurosporine yield from 8.35 mg L-1 up to 15.85 mg L-1 , whilst BV410-10 monoculture ethyl acetate extract did not have the same effect. Also, there was no improvement in staurosporine production when artificial mixed cultures were created using three different BV410-1 and BV410-10 spore ratios. CONCLUSIONS: The growth of BV410-10 was inhibited when the two strains were grown together on agar plates. Culture supernatants of BV410-10 showed potential to stimulate staurosporine production in BV410-1, but overall co-cultivation attempts did not restore the previously reported yield of staurosporine produced by the original mixed isolate. SIGNIFICANCE AND IMPACT OF STUDY: This work confirmed complex relations between streptomycetes in soil that are difficult to recreate under the laboratory conditions. Also, mining of streptomycetes genomes that mainly produce known bioactive compounds could still be the fruitful approach in search for novel bioactive molecules.

Co-cultivation of T. asperellum GDFS1009 and B. amyloliquefaciens 1841: Strategy to regulate the production of ligno-cellulolytic enzymes for the lignocellulose biomass degradation.

The influence of fossil fuels on the environment focused on the development of new technology on biofuels. In this situation, lignocellulolytic hydrolysis enzymes such as Cellobiohydrolase, ß-Glucosidase, Endoglucanase, cellulase and xylanase have broad applications in the biofuel production. The Trichoderma have used for the production of cellulase and xylanase to hydrolyze the lignocellulose. Hence, in the present study, co-culture has been employed to induce the production of polysaccharide hydrolyzing enzymes under both induction and repression conditions. The enzyme activity and its gene expression were induced by the co-culture of T. asperellum and B. amyloliquefaciens compared to the monoculture. Further, the co-culture upregulated the transcription regulatory genes and downregulated the repressor genes under both repressor and inducer conditions, respectively. The crude enzyme produced by the co-culture and monocultures using the optimized medium containing molasses, cornmeal and rice bran were further used to hydrolyze the pretreated corn Stover, rice straw, and wheat straw. These results indicate that the co-culture of T. asperellum and B. amyloliquefaciens is a promising and inexpensive method to advance the innovation on the continuous production of cellulase and xylanase under different circumstances for the bioconversion of lignocellulosic biomass into glucose for the bio-fuels.

Bioaugmentation of Bacillus amyloliquefaciens-Bacillus kochii co-cultivation to improve sensory quality of flue-cured tobacco.

Flue-cured tobacco (FCT) with irritating and undesirable flavor must be aged. However, the spontaneous aging usually takes a very long time for the low efficiency. Bioaugmentation with functional strains is a promising method to reduce aging time and improve sensory quality. To eliminate the adverse effect of excessive starch or protein content on the FCT quality, we used the flow cytometry to sort Bacillus amyloliquefaciens LB with high alpha-amylase and Bacillus kochii SC with high neutral protease from the FCT microflora. The mono, co-culture of strains was performed the solid-state fermentation with FCT. Bacillus amyloliquefaciens monoculture for 2 days and Bacillus kochii monoculture for 2.5 days achieved the optimum quality. B. amyloliquefaciens-B. kochii co-culture at a ratio of 3:1 for 2 days of fermentation showed a more comprehensive quality enhancement and higher functional enzyme activity than mono-cultivation. Through OPLS-DA model (orthogonal partial least-squares-discriminant analyzes), there were 38 differential compounds between bioaugmentation samples. In co-cultivation, most of Maillard reaction products and terpenoid metabolites were at a higher level than other samples, which promoted an increase in aroma, softness and a decrease in irritation. This result validated the hypothesis of quality improvement via the co-culture. In our study, we presented a promising bioaugmentation technique for changing the sensory attributes of FCT in a short aging time.

Enhancement of laccase production by Cerrena unicolor through fungal interspecies interaction and optimum conditions determination.

The present study aimed to identify a pair of fungal strains that promote laccase production in the co-cultivation of white-rot basidiomycetes and to determine the optimum conditions to enhance enzyme synthesis under co-fermentation of mandarin peels. Co-cultivation of Cerrena unicolor with Trametes versicolor, Lenzites betulina, and Panus lecomtei led to up-regulation of laccase activity. Moreover, interspecific interaction of Cerrena unicolor and Trametes versicolor induced the production of two new laccase isoenzymes. By contrast, interactions of Cerrena unicolor with Trametes coccineus and Trametes hirsuta resulted in a multiple decreased ability of Cerrena unicolor to produce laccase. Co-cultivation of Cerrena unicolor with other fungi 3- to 12-fold down-regulated manganese peroxidase (MnP) activity. The outcomes of these fungal interactions are closely related to the initial concentration and availability of the nutrients, the partners' inoculum ratio, time, and sequence of their inoculation. Co-cultivation of Cerrena unicolor and Trametes versicolor in fermenter resulted in the accumulation of 476 U/mL laccase and 1.12 U/mL MnP.

Co-culture of Vel1-overexpressed Trichoderma asperellum and Bacillus amyloliquefaciens: An eco-friendly strategy to hydrolyze the lignocellulose biomass in soil to enrich the soil fertility, plant growth and disease resistance.

BACKGROUND: Retention of agricultural bio-mass residues without proper treatment could affect the subsequent plant growth. In the present investigation, the co-cultivation of genetically engineered T. asperellum and B. amyloliquefaciens has been employed for multiple benefits including the enrichment of lignocellulose biodegradation, plant growth, defense potential and disease resistance. RESULTS: The Vel1 gene predominantly regulates the secondary metabolites, sexual and asexual development as well as cellulases and polysaccharide hydrolases productions. Overexpression mutant of the Trichoderma asperellum Vel1 locus (TA OE-Vel1) enhanced the activity of FPAase, CMCase, PNPCase, PNPGase, xylanase I, and xylanase II through the regulation of transcription regulating factors and the activation of cellulase and xylanase encoding genes. Further, these genes were induced upon co-cultivation with Bacillus amyloliquefaciens (BA). The co-culture of TA OE-Vel1 + BA produced the best composition of enzymes and the highest biomass hydrolysis yield of 89.56 ± 0.61%. The co-culture of TA OE-Vel1 + BA increased the corn stover degradation by the secretion of cellulolytic enzymes and maintained the C/N ratio of the corn stover amended soil. Moreover, the TA OE-Vel1 + BA increased the maize plant growth, expression of defense gene and disease resistance against Fusarium verticillioides and Cohilohorus herostrophus. CONCLUSION: The co-cultivation of genetically engineered T. asperellum and B. amyloliquefaciens could be utilized as a profound and meaningful technique for the retention of agro residues and subsequent plant growth.

Growth interferences between bacterial strains from raw cow's milk and their impact on growth of Listeria monocytogenes and Staphylococcus aureus.

AIMS: The purpose of this study was to detect growth enhancing or inhibiting activity between bacterial populations from raw milk under different conditions (temperature, medium). METHODS AND RESULTS: The interference of 24 raw milk isolates on growth of each other and on Listeria monocytogenes, Staphylococcus aureus, Bacillus subtilis and Micrococcus luteus was screened by drop assay and for selected pairs in co-cultivation experiments. By drop assay, antibacterial activity was observed for 40% of the strains. About 30% of the strains showed growth-enhancing activity on other strains. Most of the isolates were well adapted to cold temperatures and showed consistent or even increased inhibiting or enhancing effects on growth of other strains at 10°C. The growth of L. monocytogenes DSM 20600T and S. aureus DSM 1104T was significantly (P < 0·05) reduced in co-cultivation with Pseudomonas protegens JZ R-192. CONCLUSIONS: Growth interferences between bacterial populations have an impact on the structure of raw milk microbiota, especially when it develops under cold storage, and it may have an effect on the prevalence of certain foodborne pathogens. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates growth-inhibiting and also growth-enhancing interactions between raw milk bacteria, which must be considered when predicting bacterial growth and spoilage in food. A Ps. protegens strain isolated from raw milk showed an antagonistic effect on growth of L. monocytogenes in refrigerated raw milk.

Enhancement of biotransformation of ginsenosides in white ginseng roots by aerobic co-cultivation of Bacillus subtilis and Trichoderma reesei.

In the present work, the biotransformation of ginsenosides in white ginseng roots was innovatively investigated using the aerobic fermentation by the co-cultivation of Bacillus subtilis and Trichoderma reesei. It is found that in the co-cultivation mode, the optimal nitrogen source was corn steep liquor, and the loading of ginseng powder and inoculation proportion of B. subtilis and T. reesei were 15 g/L and 1:4, respectively. The total ginsenoside yield and production of minor ginsenosides in the co-cultivation mode obviously enhanced in comparison to the monoculture mode. Meanwhile, the maximal total ginsenoside yield of 21.79% and high hydrolase activities were achieved using the staged inoculation at the inoculation proportion of 1:4 in the co-cultivation mode, the production of minor ginsenosides such as Rg3 and Rh1, Rh2 was significantly strengthened, and the pharmacological activities of the fermented solution obviously improved. The enhancement of ginsenoside transformation can be mainly attributed to hydrolysis of the produced hydrolases and metabolism of two probiotics. This result clearly reveals that using the staged inoculation in co-cultivation fermentation mode was favor of the ginsenoside biotransformation in ginseng due to non-synchronous cell growth and different metabolic pathways of both probiotics. This work can provide a novel method for enhancing ginsenoside transformation of ginseng.Key points• Co-cultivation fermentation significantly promoted ginsenoside biotransformation.• The staged inoculation in co-culture mode was an optimal operation method.• The pharmacological activity of the co-cultured solution was significantly enhanced.