Low-cost Culture Research Articles

Investigation of Acetoin Biosynthesis by Bacillus subtilis ACA-DC 1176 Growing on Crude Glycerol in Flask and Bioreactor Trials

Acetoin biosynthesis by two Bacillus subtilis strains valorising crude glycerol was thoroughly explored within a pre-defined range of culture conditions and systems. B. subtilis ACA-DC 1176 stood out for its higher efficiency in acetoin production, prompting an investigation into the potential for enhanced productivity through the evaluation of diverse culture conditions and media compositions. The primary by-products of the biodiesel and corn industries, namely crude glycerol and corn steep liquor, respectively, were successfully employed as the principal carbon and nitrogen sources of the newly developed low-cost culture medium. Furthermore, the results of the various feeding strategies that were tested indicated that the conversion of 2,3-butanediol (BDO) to acetoin occurred exclusively when the concentration of glycerol was below approximately 5 g/L. This seemed to be necessary for the production of NADH, which is essential for maintaining cellular processes. Following the complete depletion of glycerol, acetic acid increased and became the predominant metabolite, while both acetoin and BDO decreased, presumably resulting in ATP generation. This is likely a mechanism employed by the cell to generate energy in the absence of a carbon source. In the fed-batch bioreactor culture, the kinetics of metabolites differed, as there was no conversion of BDO to acetoin at the final depletion of glycerol. At volumetric mass transfer coefficient (kLa) levels exceeding approximately 70 1/h, the production of acetoin was favoured over that of BDO, with the highest observed acetoin/BDO ratio reaching 4.29 g/g. Conversely, at kLa values below approximately 60 1/h, the titres of acetoin and BDO were found to be nearly equal. The final concentrations of acetoin and BDO reached 36.0 g/L and 25.5 g/L, respectively, resulting in a total yield of both (acetoin + BDO) per glycerol consumption of 0.40 g/g. To the best of our knowledge, this is the first study to focus on acetoin production from crude glycerol fermentative valorisation. The study presents new findings regarding the parameters influencing the level of BDO conversion to acetoin. However, further research is required in order to gain a comprehensive understanding of the underlying phenomena and metabolic pathways involved.

Bioprospecting Nigeria tomato cultivars against Fusarium oxysporum lycopersici under polyethylene glycol-induced drought stress

Among the vegetables, tomato is one of the economically important vegetables even at the global level. The nutritional and health benefits of tomato are so numerous to the extent that it has gained so much value in Africa due to its low-cost cultivation and contribution to livelihoods. However, Fusarium oxysporum lycopersici (FOL) and drought have been identified as potential threats to tomato production in Nigeria. To manage these challenges, one of the approaches is to identify Nigerian tomato cultivars that can exhibit resistance to FOL and drought. This study therefore investigates four Nigeria tomato cultivars; NGB00714, NGB00715, NGB00725 and NGB00740 to ascertain their resistance attributes to FOL and drought. Prior to their evaluation, Petri - dish seed germination bioassay was used in-vitro to assess the germination potentials of the tomato seeds. NGB00725 had the best germination, followed by NGB00714 and NGB00740 while the least was NGB00715. Using the Petri - dish in-vitro blotter technique, each tomato seed cultivar was separately exposed to FOL spores and FOL metabolites under drought stress induced by polyethyleneglycol (PEG-6000). Cultivar NGB00725, followed by NGB00740 exhibited resistance to FOL under PEG-induced drought stress based on their seed germination potentials. Bioprospecting resistant Nigeria tomato cultivars in this study is an indication of sustainable production of tomatoes in Nigeria against FOL under drought stress.

Plant-based vaccines against viral hepatitis: A panoptic review.

The traditional vaccines against hepatitis have been instrumental in reducing the incidence of some types of viral hepatitis; however, the need for cost-effective, easily distributable, and needle-free vaccine alternatives has led to the exploration of plant-based vaccines. Plant-based techniques offer a promising avenue for producing viral hepatitis vaccines due to their low-cost cultivation, scalability, and the potential for oral administration. This review highlights the successful expression of hepatitis B surface antigens in plants and the subsequent formation of virus-like particles, which have shown immunogenicity in preclinical and clinical trials. The challenges such as achieving sufficient antigen expression levels, ensuring consistent dosing, and navigating regulatory frameworks, are addressed. The review considers the potential of plant-based vaccines to meet the demands of rapid vaccine deployment in response to outbreaks and their role in global immunization strategies, particularly in resource-limited settings. This review underscores the significant strides made in plant molecular farming and the potential of plant-based vaccines to complement existing immunization methods against viral hepatitis.

Upcycling food waste as a low-cost cultivation medium for Chlorella sp. microalgae.

Global food loss and waste have raised environmental concerns regarding the generation of greenhouse gases (e.g., carbon dioxide and methane gas), which directly contribute to climate change. To address these concerns, the present research aims to upcycle food waste into an alternative culture medium for the cultivation of microalgae. Various parameters including pretreatment of food waste (i.e., autoclave and non-autoclave), concentration of food waste culture medium (i.e., 10%, 30%, 50%, 70%, 90% and 100%), harvesting efficiency and biochemical compounds of Chlorella sp. microalgae were carried out. Based on the preliminary findings, the highest biomass concentration obtained from 10% food waste culture medium in the autoclave for Chlorella sp., including strains FSP-E, ESP-31 and CY-1, were 2.869 ± 0.022, 2.385 ± 0.018 and 0.985 ± 0.0026 g L-1, respectively. Since Chlorella vulgaris FSP-E exhibited the highest biomass concentration, this microalgal strain was selected to examine the subsequent parameters. Cultivation of C. vulgaris FSP-E in 100FW achieves a biomass concentration of 4.465 ± 0.008 g L-1 with biochemical compounds of 6.94 ± 1.396, 248.24 ± 0.976 and 406.23 ± 0.593 mg g-1 for lipids, carbohydrates and proteins, respectively. This study shows that using food waste as an alternative culture medium for C. vulgaris FSP-E can achieve substantial biomass productivity and biochemical content. This research work would contribute to the concept of net zero emission and transitioning toward a circular bioeconomy by upcycling food waste as an alternative culture medium for the cultivation of microalgae. © 2024 Society of Chemical Industry.

A low-cost culture- and DNA extraction-free method for the molecular detection of pneumococcal carriage in saliva.

Molecular methods have improved the sensitivity of the detection of pneumococcal carriage in saliva. However, they typically require sample culture enrichment and nucleic acid extraction prior to performing the detection assay and may limit scalability for extensive surveillance of pneumococcus, particularly in low-resource settings. We evaluated the performance of a DNA-extraction-free method for the detection of pneumococcus in saliva. We developed a streamlined qPCR-based protocol for the detection of pneumococcus, omitting culture enrichment and DNA extraction. Using saliva samples collected from children attending childcare centers (New Haven, CT, USA), we evaluated the detection of pneumococcus using saliva lysates as compared to purified DNA extracted from culture-enriched aliquots of the paired samples using qPCR targeting the pneumococcal piaB gene. Of the 759 saliva samples tested from 92 children [median age 3.65 years; IQR (2.46-4.78)], pneumococcus was detected in 358 (47.2%) saliva lysates prepared using the extraction-free protocol and in 369 (48.6%) DNA extracted from culture-enriched samples. We observed near-perfect agreement between the two protocols (Cohen's kappa: 0.92; 95% CI: 0.90-0.95). Despite a high correlation between CT values generated by the two methods (r = 0.93, P < 0.0001), the CT values generated from saliva lysates were higher (lower concentration) than those from culture-enriched samples (ΔCT = 6.69, P < 0.00001). The cost of detecting pneumococcus using saliva lysates was at least fivefold lower (US$2.53) compared to the cost of the culture-enriched method (range: US$13.60-US$19.46). For pneumococcal carriage surveillance in children, our findings suggest that a DNA extraction-free approach may offer a cost-effective alternative to the resource-intensive culture-enrichment method.IMPORTANCESurveillance for carriage of pneumococcus is a key component of evaluating the performance of pneumococcal vaccines and informing new vaccination strategies. To improve the scalability of pneumococcal carriage surveillance, we show that molecular detection of pneumococcus in saliva from children can be performed without culture enrichment and DNA extraction. Our findings show that using the extraction-free method can improve surveillance efforts for pneumococcal carriage in children, overcoming the resource-intensive hurdle that comes with the use of molecular methods, particularly in low-resource settings.

Use of microalgal-fungal pellets for hydroponics effluent recycling and high-value biomass production

Hydroponic effluent (HE), enriched with inorganic nutrients, presents a viable, low-cost cultivation medium for microalgal biomass production and subsequent resource recovery. However, downstream processing, particularly biomass harvesting, remains a critical challenge for microalgal biorefineries. Therefore, the present study explored the potential of microalgal-fungal pellets (MAFP) in HE recycling for the production of biochemical-rich biomass. The optimized fungi-to-microalgae ratio (F:A) of 1:3 resulted in 100 % microalgal pelletization within 6 h. Surface characteristics suggested that metabolically active fungi with opposite charges facilitate microalgal pelletization. Further, MAFP exhibited a packed porous structure that was resilient to shear forces and had a high capacity for nutrient uptake. MAFP cultivation in HE demonstrated complete removal of ammonia-nitrogen (NH₃-N), phosphate (PO₄³⁻), and nitrate-nitrogen (NO₃⁻-N) within 7–9 days. The produced biomass was rich in biomolecules, including lipids (18.36 ± 0.12 % TS), protein (52.06 ± 2.1 % TS), and carbohydrates (28.95 ± 0.05 % TS). Besides, the high methane potential of MAFP (SMP ≈ 502.74 ± 19.1 mL CH4 g−1 VS, and TMP ≈ 817.68 ± 12.5 mL CH4 g−1 VS) indicated its suitability for biogas production. In essence, MAFP offers efficient HE recycling and biochemically rich biomass production, advancing towards a green and circular bioeconomy.

Sustainable production of nutritional iron-enriched yeast from low-cost bran sources: A valuable feedstock for circular economy

Enhancing iron bioavailability through iron-enriched yeast offers a promising nutritional solution. This study explores the sustainable production of iron-enriched yeast using soybean, corn, and wheat bran hydrolysates as low-cost culture media in submerged fermentation. Culture mediums were supplemented with 15 mg L−1 of Fe+2. Iron-yeast production was successful using starchy hydrolysates due to their rich composition. Soybean bran hydrolysate achieved the highest biomass production (7.9 g L−1 dry cell), corn bran hydrolysate accomplished the largest iron incorporation (3.18 mg of iron/gram of dry cell); while supplemented wheat hydrolysate attained the greatest yield (2.58 ± 0.68 g/g). This research showed high potential on the production of iron-enriched yeast biomass from starchy hydrolysates, and the potential production of health and food products through sustainable production methods.

Graft take outcomes of burn patients transplanted with CEA derived from a modified composite culture technique: A case series.

Low-cost and efficient culture environments comparable to standard techniques would undoubtedly improve burn outcomes in under-resourced settings. The aim of this case series was to report on the CEA graft-take using a modified composite culture technique. CEA transplants, following emergency ethical approval, occurred for burn patients (n=25) with low survival prognosis and/or exhausted donor sites. Keratinocytes were retrieved from skin biopsies, seeded centrally on routinely-used dressing gauze and incubated at 37 °C in pediatric incubators. Fresh autogenous plasma was applied daily and hydrogel every third or fourth day. After confluence, the CEA was transplanted onto debrided wound beds. Xenografts were used for temporary cover during the culture period. Final graft take assessment (21 days) was assessed and calculated as a graft take percentage for total CEA area transplanted. Central indices were described as mean (95% CI) and frequency (%) for age, total body surface area, abbreviated burn severity index scores, survival prognosis and graft take. Eleven patients survived with a mean age of 36.1 years (95% CI 25.8-46.4), 45.0 %TBSA burns (95% CI 35.1-54.9), 9.7 ABSI scores (95% CI 8.6-10.8) and 79.5% graft take (95% CI 62.9-96.0). Reduced graft take (61.2%) was observed in patients with perineum burns and increased graft take (97%) in uncomplicated burns. The average CEA graft take was 79.5% using a low-cost culture technique and comparable to the largest case series in literature. The survival of the major burn cases was highly favourable considering injury severity, expected outcomes without CEA and the observed challenges.

Co-expression of human sialyltransferase improves N-glycosylation in Leishmania tarentolae and optimizes the production of humanized therapeutic glycoprotein IFN-beta

The production of therapeutic glycoproteins is primarily expensive due to the necessity of culturing mammalian cells. These systems often require complex and costly culture media and typically yield low amounts of protein. Leishmania tarentolae, a non-pathogenic protozoan to mammals, has emerged as a cost-effective alternative system for heterologous glycoprotein expression due to its suitability for large-scale production using low-cost culture media, and its ability to perform mammalian-like post-translational modifications, including glycosylation. Nevertheless, differences in the carbohydrate residues at the end of N-glycan chains are observed in Leishmania compared to mammalian cells due to the absence of biosynthetic enzymes in Leishmania that are required for the incorporation of terminal sialic acid. In this study, a genetically optimized L. tarentolae cell line was engineered for the production of recombinant interferon-β (IFN-β) featuring a complete mammalian N-glycosylation profile. Genomic and metabolomic analyses revealed that heterologous expression of the sialyltransferase enzyme and cultivation in a medium containing sialic acid were sufficient to generate mammalian-like protein N-glycosylation. N-glycan mass spectrometry analysis demonstrated a glycosylation pattern compatible with the incorporation of sialic acid into the glycan structure. In vitro IFN-β activity indicated that the expressed protein exhibited reduced inflammatory effects compared to IFN-beta produced by other platforms, such as bacteria, non-optimized L. tarentolae, and mammalian cells.

The Nutritional Quality of the Culture Medium Influences the Survival of Non-Saccharomyces Yeasts Co-Cultured with Saccharomyces cerevisiae

Yeast-yeast interactions have been studied mainly using wine yeasts. However, studies are rare for native yeasts from agave juice fermentation. Therefore, this work used strains isolated from the alcoholic fermentation of agave to study the survival of non-Saccharomyces yeasts co-cultivated with Saccharomyces cerevisiae in media of different nutritional qualities. First, the feasibility of using simple and low-cost culture media was demonstrated to study the interactions between Saccharomyces cerevisiae and non-Saccharomyces yeasts. The results presented here demonstrated the antagonistic effect exerted by S. cerevisiae on Torulaspora delbrueckii, which showed a more significant loss of viability. However, the nutritional composition of the culture medium also influences this effect. It was clear that a nutritionally rich medium improved the survival of non-Saccharomyces yeasts. Lastly, the change in the survival of non-Saccharomyces yeasts also entails a variation in the concentration and diversity of minor volatile compounds produced during fermentation. This was observed in the variety and relative abundance of compounds belonging to the most numerous chemical families, such as alcohols, esters, and terpenes.

Production of low-cost lactic acid from dairy wastes and dates wastewater and bioactive silver-poly (lactic acid) nanocomposite for biological applications

L-Lactic acid-producing Lactobacillus lactis and L. plantarum were isolated from date wastes. The fermentation process was optimized using a one-variable-at-a-time approach. Dairy wastewater and wastewater from the date industry were utilized as low-cost culture media to produce lactic acid. The selected two bacterial strains were co-cultured in wastewater medium to produce L-lactic acid and D-lactic acid. Lactic acid production was significantly improved by glucose (carbon source), yeast extract (nitrogen source), initial inoculum level, and polysorbate 80. A central composite design and response surface methodology were used to optimize the variables and their levels to improve lactic acid yield. The supplemented yeast extract, glucose, and polysorbate 80 improved lactic acid. The predicted variables and their levels for maximum lactic acid production were glucose (67.5 g/L), yeast extract (10.28 g/L), and polysorbate 80 (0.48 mL/L). The prepared nanocomposites exhibited antibacterial activity against foodborne bacterial pathogens. The structural properties of the silver-polylactic acid nano compost materials were determined. The characterized compost materials exhibited a peak absorption wavelength of 430 nm. The silver and poly(lactic acid) were characterized using X-ray diffraction analysis and were 30 to 50 nm in size.

Low-cost cultivation of Nannochloropsis oceanica in newly designed photobioreactors and its productivity trends in semi-continuous cultivation under inland outdoor conditions

Most marine microalgae are typically cultivated in coastal areas due to challenges in inland cultivation. In this 185 days experiment, Nannochloropsis oceanica was semi-continuously cultivated inland using different photobioreactors (PBRs). The newly designed 700-liter (L) PBR exhibited tolerance to seasonal changes compared to the 150-L PBRs. The innovative in-situ oxygen release rate (ORR) measurement method results indicated that ORR was influenced by light intensity and temperature. The optimal temperature range for N. oceanica growth was 14–25 ℃, demonstrated cold tolerance and lipid accumulation at low temperatures. The maximum lipid content in 700-L and 150-L PBRs was 29 % and 28 %, respectively. Based on the average biomass productivity, the price of N. oceanica was $11.89 kg−1 (or $3.35 kg−1 based on maximum biomass productivity), which is cheaper than the current market price of $20.19 kg−1. From results, smaller PBRs at the same hydro electricity price are more cost-effective.

Pilot-scale production of Bacillus subtilis MSCL 897 spore biomass and antifungal secondary metabolites in a low-cost medium.

Bacillus subtilis is a plant growth promoting bacterium (PGPB) that acts as a microbial fertilizer and biocontrol agent, providing benefits such as boosting crop productivity and improving nutrient content. It is able to produce secondary metabolites and endospores simultaneously, enhancing its ability to survive in unfavorable conditions and eliminate competing microorganisms. Optimizing cultivation methods to produce B. subtilis MSCL 897 spores on an industrial scale, requires a suitable medium, typically made from food industry by-products, and optimal temperature and pH levels to achieve high vegetative cell and spore densities with maximum productivity. This research demonstrates successful pilot-scale (100L bioreactor) production of a biocontrol agent B. subtilis with good spore yields (1.5×109 spores mL-1) and a high degree of sporulation (>80%) using a low-cost cultivation medium. Culture samples showed excellent antifungal activity (1.6-2.3cm) against several phytopathogenic fungi. An improved methodology for inoculum preparation was investigated to ensure an optimal seed culture state prior to inoculation, promoting process batch-to-batch repeatability. Increasing the molasses concentration in the medium and operating the process in fed-batch mode with additional molasses feed, did not improve the overall spore yield, hence, process operation in batch mode with 10g molasses L-1 is preferred. Results also showed that the product quality was not significantly impacted for up to 12months of storage at room temperature. An economically-feasible process for B. subtilis-based biocontrol agent production was successfully developed at the pilot scale.

Assessment of molecular and metabolic traits of a newly isolated Spirulina platensis BERC15 in a low-cost cultivation alternative for its use as functional food

Commercial cultivation of Spirulina relies on expensive chemicals. This study aimed to optimize low-cost cultivation media for upscaling of the Spirulina cultivation for food applications. Here, low-cost nitrogen source resulted in 3 gL−1 of biomass while outdoor pilot-scale cultivation produced 6.5–9.6 g m−2day−1 of biomass. The growth media prepared in underground water (UGW) using commercial-grade chemicals (UGW + CC) was found to be the most suitable low-cost alternative media which produced 2.3 ± 0.28 gL−1 of biomass containing 56 ± 1.22 % proteins, 22 ± 1.88 % carbohydrates, and 12 ± 2.52 % lipids. GC–MS-based metabolomic analysis implied that only four metabolites were either down or upregulated out of 50 detected metabolites. The Hep G2 cancer cell line-based study showed 15-fold higher free radical scavenging activity in UGW + CC grown cells compared to control. This study provides a basis for process optimization towards commercial-scale cultivation of Spirulina using small and medium enterprise mode.

Tofu Whey-Based Media for Probiotic Lactiplantibacillus plantarum D4 as a Halal Starter Culture

In recent years, the development of probiotic-based fermented products with halal status has been a concern. The use of growth medium has relied on de Man Rogosa and Sharpe (MRS) as a relatively expensive standard medium, and its halal status is still uncertain. Extensive research has been carried out to investigate the development of low-cost halal alternative media for the cultivation of probiotic lactic acid bacteria (LAB). This study aimed to develop a probiotic halal and low-cost culture medium using a tofu whey-based medium. This study used three tofu whey-based media – A (tofu whey 100%), B (tofu whey 94.5%, molasses 3%, skim milk 2.5%), C (tofu whey 92.5%, molasses 3%, cheese whey 2.5%, tomato extract 2%), and MRS broth as a standard medium. Bacterial populations, total sugars utilized, total lactic acids produced, low pH (2.0) tolerance, and high bile salt concentration (oxgall 1.5%) were assayed. The highest bacterial population after 48 h of incubation was shown by medium B compared to medium MRS (12.34 ± 0.87 and 11.48 ± 0.3 log CFU/mL). Total sugars utilized by 48.28 ± 2.89, 38.89 ± 6.94, 39.14 ± 4.24, and 76.00 ± 1.41 %; on the other hand, total lactic acids produced by 0.16 ± 0.12, 0.03 ± 0.04, 0.31 ± 0.03, and 2.25 ± 1.48 % in A, B, C, and MRS, respectively. Probiotic tolerance at low pH and the presence of bile salts of Lactiplantibacillus plantarum D4 consistently showed a high survival rate in medium B compared to MRS. Based on these results, the components and proportions used in medium B were suitable for the growth of L. plantarum D4 as a halal probiotic starter candidate.

Optimization of Expression and Purification of Recombinant One of Central Nervous System Enzyme (Acetylcholinesterase)

In general, the use of natural enzymes is very limited and they are not economical to use in industry. To solve this problem, the recombinant expression systems approach has been used. Optimization of production processes in heterologous expression systems is one of the most important activities in today's competitive industries. One of the key factors for the commercialization of recombinant proteins is the achievement of a low-cost culture medium available for the production of suitable cell biomass that can be used on an industrial scale. Commercialization of recombinant products requires process economics and cost reduction, and reducing the cost of the product is possible by using a cheaper culture medium, so decided optimization of expression and purification of recombinant acetylcholinesterase (EC.3.1.1.7), because it’s one of the body's vital enzymes, that by hydrolyzing acetylcholine, which is a neurotransmitter, terminates neural messages in the area of cholinergic synapses. Because the enzyme acetylcholinesterase produced from natural sources is not suitable for industrial purposes and semi-mass production due to low production efficiency and high costs of enzyme preparation and purification processes, optimizing the growth conditions of microorganisms capable of the production and secretion of the enzyme acetylcholinesterase are very important, both in terms of yield and economic costs. The present study seeks to increase productivity and reduce the cost of producing this enzyme by optimizing the growth medium and expression of pichia pastoris yeast cells that have genes related to this enzyme and also by optimizing the purification and mass production of this enzyme.

Development of an alternative low-cost culture medium for a new isolated high-production DHA strain using kitchen wastewater

Docosahexaenoic acid (DHA) is a high-value polyunsaturated fatty acid. The industrial development of microbial DHA was restricted due to high medium cost. Kitchen wastewater was always rich in nitrogen, phosphorous, carbohydrates, which can be used for microorganism growth. This study developed of a primitive low-cost culture medium for a new isolated high-production DHA strain using kitchen wastewater. The results showed that, a total of 66 strains were isolated from mangrove habitats. The highest DHA-producing strain N6 was identified as Aurantiochytrium sp. (GenBank accession number OL455742) with a DHA production of 6.56 g/L. Then the optimization of kitchen wastewater medium was designed by Response Surface Methodology, and 7.14 ∼ 7.23 g/L of DHA production was obtained. At the same time, the lipid content in Aurantiochytrium sp. N6 was as high as 75.68%, which contributed to the increase of DHA production in optimal kitchen wastewater medium. Finally, the substrate cost of kitchen wastewater medium was reduced by 43.95%. Meanwhile, the dissolved organic carbon (DOC), dissolved nitrogen (DN) and dissolved phosphorus (DP) in kitchen wastewater were utilized by Aurantiochytrium sp. N6 more than 90%. This work enriched the competitive candidate DHA-producing microbes, and provided a perceptive idea for both the medium substrate cost reducing and kitchen wastewater recycling.

Establishment of an Efficient Expression and Regulation System in Streptomyces for Economical and High-Level Production of the Natural Blue Pigment Indigoidine.

Indigoidine, as a kind of natural blue pigment, is widely used in textiles, food, and pharmaceuticals and is mainly synthesized from l-glutamine via a condensation reaction by indigoidine synthetases, most of which originates from Streptomyces species. However, due to the complex metabolic switches of Streptomyces, most of the researchers choose to overexpress indigoidine synthetases in the heterologous host to achieve high-level production of indigoidine. Considering the advantages of low-cost culture medium and simple culture conditions during the large-scale culture of Streptomyces, here, an updated regulation system derived from the Streptomyces self-sustaining system, constructed in our previous study, was established for the highly efficient production of indigoidine in Streptomyces lividans TK24. The updated system was constructed via promoter mining and σhrdB expression optimization, and this system was applied to precisely and continuously regulate the expression of indigoidine synthetase IndC derived from Streptomyces albus J1704. Finally, the engineered strain was cultured with cheap industrial glycerol as a supplementary carbon source, and 14.3 and 46.27 g/L indigoidine could be achieved in a flask and a 4 L fermentor, respectively, reaching the highest level of microbial synthesis of indigoidine. This study will lay a foundation for the industrial application of Streptomyces cell factories to produce indigoidine.

Evaluation of Scenedesmus dimorphus under Different Photoperiods with Eutrophicated Lagoon Water

Given the need to improve bioenergy production processes, it is necessary to focus on low-cost culture media and environmental conditions of radiation and temperature. The Scenedesmus dimorphus species was cultured in eutrophicated lagoon water and Bayfolan 0.3% as culture media under four photoperiods with the objective of evaluating the biomass productivity, bioremediation capacity and influence of illumination on the composition and lipid content. It is concluded that the increase of light hours in the culture with eutrophicated lagoon water produces a decrease in the biomass productivity and COD removal percentage. The highest biomass productivity was obtained in photoperiod F1 (10.5:13.5) hours L:O, 0.053 ± 0.0015 g/L day and a removal of 95.6%. Bayfolan 0.3% with F2 (11.5:12.5) and F3 (12.5:11.5) did not show significant differences in the biomass productivity and COD removal. The increase in light hours in the photoperiod induced an increase of 1.01% and 2.84% of saturated fatty acids and 0.8% and 2.14% of monounsaturated fatty acids, as well as a decrease of 3.85% and 2.88% of polyunsaturated fatty acids in eutrophicated lagoon water and Bayfolan 0.3%, respectively.

Reducing costs, improving profits: A low-cost culture media for woody plants micropropagation

Reducing costs, improving profits: A low-cost culture media for woody plants micropropagation