Total Fatty Acid Production Research Articles

Evaluation of Pre-ingestive Citronella Residues using Ruminal In Vitro Techniques

Citronella residues (CR) have the potential to be used as an alternative to the fiber diet of ruminants. This study reports on the effects of pre-ingestive CR using ammonia (4 % dry matter (DM)) and fermentation (6 % DM) on in vitro rumen fermentation, metabolism, and methane (CH4) production. Four CR levels of 0, 25, 75, and 100 % DM were used. Each level was repeated 3 times and a complete randomized design method was used. The results showed that pre-ingestive CR significantly increased the pH rumen fluid but decreased ammonia-nitrogen concentration, total iso-volatile fatty acid (iso-VFA) production, and protozoa population (p < 0.01). The pre-ingestive CR significantly decreased the acetic acid composition and rumen microbial protein synthesis (p < 0.05), and significantly increased the proportion of propionic acid, n-butyric acid, and iso-valeric acid (p < 0.05). The total VFA production and rumen CH4 production did not significantly change (p > 0.05). In conclusion, pre-ingestive CR was compatible as a basal diet for ruminants.
 HIGHLIGHTS
 
 Pre-ingestive treated citronella residues used as substitute in ruminant fiber diet
 100 % pre-ingestive citronella residues increased rumen fluid pH compared with napier grass
 100 % pre-ingestive citronella residues reduced NH3, VFA, and protozoa
 100 % pre-ingestive citronella residues had no effect on methane production
 Rumen fermentation profile of pre-ingestive residue treatments are suitable alternative diets
 
 GRAPHICAL ABSTRACT

Dietary Supplementation of Chitosan Oligosaccharide-Clostridium butyricum Synbiotic Relieved Early-Weaned Stress by Improving Intestinal Health on Pigeon Squabs (Columba livia).

According to a previous study, we had found that early weaning causes harm to growth performance, intestinal morphology, activity of digestive enzymes, and antioxidant status in pigeon squabs (Columba livia). Chitosan oligosaccharides (COS) and Clostridium butyricum have been reported to have great potential to improve the growth performance and intestinal health of early-weaned animals. Therefore, the aim of this study is to explore whether dietary supplementation with COS-C. butyricum synbiotic could relieve early-weaned stress by evaluating its effects on growth performance and intestinal health in pigeon squabs. A total of 160 squabs (weaned at 7 days of age) were randomly divided into 5 groups: the control group, fed with artificial crop milk; the COS supplementation group, fed with artificial crop milk + 150 mg/kg COS; and three synbiotic supplementation groups, fed with artificial crop milk + 150 mg/kg COS + 200, 300, and 400 mg/kg C. butyricum. The results showed that a diet supplemented with COS-C. butyricum synbiotic benefitted the growth performance of early-weaned squabs; even so the differences were not significant among the five groups (p > 0.05). In addition, dietary supplementation of 150 mg/kg COS + 300~400 mg/kg C. butyricum significantly improved the intestinal morphology (especially villus surface area and the ratio of villus height to crypt depth), the activity of digestive enzymes (lipase, trypsin, and leucine aminopeptidase) in duodenum contents, and the production of total short-chain fatty acids and acetic acid in ileum content (p < 0.05). Additionally, dietary supplementation of 150 mg/kg COS + 400 mg/kg C. butyricum benefitted gut health by improving the antioxidant capacity (glutathione peroxidase and total antioxidant capacity) and cytokine status (IL-4 and IL-10) (p < 0.05), as well as by improving the intestinal microbiota diversity. In conclusion, our results revealed that dietary supplementation with synbiotic (150 mg/kg COS + 300~400 mg/kg C. butyricum) could relieve early-weaned stress by maintaining intestinal health in pigeon squabs.

Microbiota-Independent Spontaneous Dermatitis Associated with Increased Sebaceous Lipid Production in Tmem79-Deficient Mice

TMEM79 is a predisposing gene for atopic dermatitis. Tmem79-deficient mice develop spontaneous dermatitis in a biphasic pattern. The first-phase dermatitis is unique because it occurs independent of microbiota status, whereas the second-phase dermatitis is microbiota dependent. In this study, we sought to identify the key factors mediating the development of first-phase dermatitis. Structural analysis showed that sebaceous gland hyperplasia started from first-phase dermatitis. Longitudinal RNA sequencing analysis revealed significant activation of fatty acid lipid metabolism pathways in first-phase dermatitis, whereas T helper 17‒based immune response genes were highly expressed in second-phase dermatitis. Quantitative RT-PCR analysis revealed that genes involved in fatty acid elongation and sebocyte differentiation were upregulated in first-phase dermatitis. The results of thin-layer chromatography supported these findings with an increased abundance of wax esters, cholesterol esters, and fatty alcohols in hair lipids. Further gas chromatography-tandem mass spectrometry analysis showed an increase in total fatty acid production, including that of elongated C20-24 saturated and C18-24 monounsaturated fatty acids. Collectively, these results suggest that aberrant production of sebaceous long-chain fatty acids is associated with microbiota-independent dermatitis. Further investigation of Tmem79-deficient mice may clarify the role of certain fatty acids in dermatitis.

Evaluation of Different Standard Amino Acids to Enhance the Biomass, Lipid, Fatty Acid, and γ-Linolenic Acid Production in Rhizomucor pusillus and Mucor circinelloides.

In this study, 18 standard amino acids were tested as a single nitrogen source on biomass, total lipid, total fatty acid (TFA) production, and yield of γ-linolenic acid (GLA) in Rhizomucor pusillus AUMC 11616.A and Mucor circinelloides AUMC 6696.A isolated from unusual habitats. Grown for 4 days at 28°C, shaking at 150 rpm, the maximum fungal biomass for AUMC 6696.A was 14.6 ± 0.2 g/L with arginine and 13.68 ± 0.1 g/L with asparagine, when these amino acids were used as single nitrogen sources, while AUMC 11616.A maximum biomass was 10.73 ± 0.8 g/L with glycine and 9.44 ± 0.6 g/L with valine. These were significantly higher than the ammonium nitrate control (p < 0.05). The highest levels of TFA were achieved with glycine for AUMC 11616.A, 26.2 ± 0.8% w/w of cell dry weight, and glutamic acid for AUMC 6696.A, 23.1 ± 1.3%. The highest GLA yield was seen with proline for AUMC 11616.A, 13.4 ± 0.6% w/w of TFA, and tryptophan for AUMC 6696.A, 12.8 ± 0.3%, which were 38% and 25% higher than the ammonium tartrate control. The effects of environmental factors such as temperature, pH, fermentation time, and agitation speed on biomass, total lipids, TFA, and GLA concentration of the target strains have also been investigated. Our results demonstrated that nitrogen assimilation through amino acid metabolism, as well as the use of glucose as a carbon source and abiotic factors, are integral to increasing the oleaginicity of tested strains. Few studies have addressed the role of amino acids in fermentation media, and this study sheds light on R. pusillus and M. circinelloides as promising candidates for the potential applications of amino acids as nitrogen sources in the production of lipids.

Enhancement of Astaxanthin and Fatty Acid Production in Haematococcus pluvialis Using Strigolactone

Improving the production rate of high-value nutraceutical compounds, such as astaxanthin and polyunsaturated fatty acids (PUFAs), is important for the commercialization of Haematococcus pluvialis biorefineries. Here, the effects of a phytohormone, strigolactone analog rac-GR24, on cell growth and astaxanthin and fatty acid biosynthesis in H. pluvialis were investigated. Four concentrations (2, 4, 6, and 8 µM) of rac-GR24 were initially added during 30 days of photoautotrophic cultivation. The addition of rac-GR24 improved cell number density and chlorophyll concentration in H. pluvialis cultures compared to the control; the optimal concentration was 8 µM. Despite a slightly reduced astaxanthin content of 30-d-old cyst cells, the astaxanthin production (26.1 ± 1.7 mg/L) improved by 21% compared to the rac-GR24-free control (21.6 ± 1.5 mg/L), owing to improved biomass production. Notably, at the highest dosage of 8 µM rac-GR24, the total fatty acid content of the treated H. pluvialis cells (899.8 pg/cell) was higher than that of the untreated cells (762.5 pg/cell), resulting in a significant increase in the total fatty acid production (361.6 ± 48.0 mg/L; 61% improvement over the control). The ratio of PUFAs, such as linoleic (C18:2) and linolenic (C18:3) acids, among total fatty acids was high (41.5–44.6% w/w) regardless of the rac-GR24 dose.

The Mediterranean Diets’ Effect on Gut Microbial Composition in Comparison with the Western Diet: A Literature Review

Background: In recent years, the scientific interest about the possible role of dietary attitudes on gut microbiota modulation has been increasing. Objective: The present literature review aimed to analyze the effect of Mediterranean diet adoption on gut microbial composition, in comparison with the Western diet. Method: From an initial number of 38, 21 recent studies were selected using comprehensive scientific databases and relative keywords, such as microbial composition, dietary attitudes, and beneficial effects. The selected studies were recently published based on animal models, human interventional trials, metanalyses and gut microbiome analysis, such as metagenomics. Results: According to the basic findings of the present review study, Mediterranean diet adherence leads to a gut microbial richness and richer diversity as well as a higher abundance of genera Lactobacillus, Faecalibacterium, Oscillospira, Bifidobacterium, Eubacterium species, that stimulate the production of total short-chain fatty acids. This diet also leads to a lower Firmicutes / Bacteroidetes ratio due to the increase of Bacteroidetes and decrease of Firmicutes, accompanied by a decrease of circulating Trimethylamine N oxide levels and a reduction in abundance of Ruminococcus, Lachnospiraceae, Proteobacteria and Coprococcus, in comparison to the Western diet. Conclusion: Further understanding of the multifactorial effect of both Mediterranean and Western diet on gut microbiota could allow the establishment of nutritional educational programs and nutritional policies with aim to improve human health by modulating gut microbial composition.

Gut microbiota can utilize prebiotic birch glucuronoxylan in production of short-chain fatty acids in rats.

Birch-derived glucuronoxylan (GX)-rich hemicellulose extract is an abundantly available by-product of the forest industry. It has multifunctional food stabilizing properties, and is rich in fiber and polyphenols. Here, we studied its effects on colonic metabolism and gut microbiota in healthy rats. Male and female Wistar rats (n = 42) were fed AIN-93G-based diets with 10% (w/w) of either cellulose (control), a polyphenol and GX-rich extract (GXpoly), or a highly purified GX-rich extract (pureGX) for four weeks. Both the GXpoly and pureGX diets resulted in changes on the gut microbiota, especially in a higher abundance of Bifidobacteriaceae than the cellulose containing diet (p < 0.001). This coincided with higher concentrations of microbial metabolites in the luminal contents of the GX-fed than control rats, such as total short-chain fatty acids (SCFAs) (p < 0.001), acetate (p < 0.001), and N-nitroso compounds (NOCs) (p = 0.001). The difference in the concentration of NOCs was not seen when adjusted with fecal weight. GX supplementation supported the normal growth of the rats. Our results indicate that GXpoly and pureGX can favorably affect colonic metabolism and the gut microbiota. They have high potential to be used as prebiotic stabilizers to support more ecologically sustainable food production.

Plug-flow reactor for volatile fatty acid production from the organic fraction of municipal solid waste: Influence of organic loading rate

This work experimentally assessed the production of total and specific volatile fatty acids (VFAs) by dry thermophilic anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) in a semi-continuous pilot-scale plug-flow reactor (PFR). The experimental test compared the two organic loading rates (OLR) of 7.5 and 14 gVS/(L d) for an overall duration of 150 days. The results revealed that OLR positively affects the production of total VFAs, since their overall concentration reached a maximum of 12136 mg/L with OLR of 14 gVS/(L d). In addition, the productivity increased by 150.9% and the yield increased by 49.2% compared to the lowest OLR tested. Propionate dominated during the whole experimental period ranging between 86.2% and 64.4% of total VFAs. As the OLR increased, the concentration of iso-valeric and butyric acids increased as well, accounting for 15.7% and 9.6% of total VFAs, respectively. Meanwhile, the specific biogas production (SGP) decreased from 280.8 ± 72.8–196.3 ± 24.4 NLbiogas/kgVS diminishing by 30.6%, and the oxygen uptake rate (OUR) raised from 46.4 ± 0.6–124.8 ± 10.9 mmolO2/(kgVS h) increasing by 169.1%.

The effects of Pinus brutia bark extract on pure and mixed continuous cultures of rumen bacteria and archaea, and fermentation characteristics in vitro

The aim of the study was to investigate the effects of Pinus brutia bark extract, which is rich in polyphenolic compounds of tannins, on both pure and mixed continuous cultures of rumen bacteria and archaea, as well as on rumen fermentation characteristics in vitro. Antimicrobial susceptibility assay with pure cultures was carried out in an anaerobic chamber. Pinus brutia bark extract exhibited a potential inhibitor activity (P&lt;0.05) against pure cultures of Ruminococcus flavefaciens, Eubacterium ruminantium, and Methanobacterium formicicum while a growth stimulatory effect (P&lt;0.05) was observed for Ruminoccocus albus, Butyrivibrio fibrisolvens, and Streptococcus bovis. Pinus brutia bark extract only had a potential inhibitor effect (P&lt;0.05) on R. albus at the highest dose (1200 µg/mL). Pinus brutia bark extract also stimulated (P&lt;0.05) the growth of pure cultures of Fibrobacter succinogenes, while it did not affect Megasphaera elsdenii, except at the highest dose. The effects of two doses (75 and 375 mg/L) of P. brutia bark extract on in vitro mixed cultures and rumen fermentation parameters were determined by the rumen simulation technique (Rusitec). Supplementation with P. brutia bark extract led to a quadratic decrease (P&lt;0.05) in the cell numbers of R. flavefaciens. Production of total and individual short chain fatty acids (SCFA), acetate to propionate ratio (C2/C3), total protozoa, ruminal pH, and dry matter digestibility (DMD) did not change in the presence of P. brutia bark extract. Supplementation with both doses of P. brutia bark extract decreased (P&lt;0.05) the ammonia-N concentrations. Ammonia-N concentration was lowest in the high-supplemented group (P&lt;0.05). As a conclusion, inhibitory effects of P. brutia bark extract on some species in the pure cultures were in the same direction as with mixed ruminal cultures, while stimulatory effects disappeared. The lack of inhibitory effects on protozoa and on a large number of Gram-positive rumen bacteria in the mixed cultures suggests that its mechanism of action is not exactly similar to antibiotics. Although P. brutia bark extract did not alter ruminal SCFA, it could have potential to improve ruminal protein utilization without depressing rumen microbial fermentation.

Effect of phytase and carbohydrases supplementation on digestibility, palatability, fecal characteristics and fecal fermentation products in dogs fed plant-protein diet

The use of exogenous enzymes in canine nutrition has been studied as a way to improve the nutritional value of plant by-products. This study conducted 2 experiments to evaluate the effects of exogenous phytase and a complex of carbohydrases supplementation on plant protein based diets for dogs. Dietary treatments consisted of an animal protein-based diet (AD; poultry offal meal and meat-and-bone meal) without enzyme inclusion; a plant protein-based (PD; soybean meal) without enzymes, considered the control diet; PD + 5000 phytase units (FTU)/g (PD + P5); PD + 10,000 FTU/g (PD + P10); PD + 15,000 FTU/g (PD + P15); PD + 50,000 units of a carbohydrase enzyme complex (U)/g (PD + C); PD + a combination of 5000 phytase units FTU/g and 50,000 units of a carbohydrase complex U/g (PD + PC). In experiment 1, 14 dogs were fed the experimental diets and distributed in a randomized block design to assess digestibility, fecal characteristics, and fecal fermentation products. In experiment 2, a palatability test was evaluated in pairs by the means of two comparisons: PD vs. PD + PC and PD + P5 vs. PD + PC, with 16 dogs. The inclusion of PD + PC did not alter the digestibility of the diet (P > 0.05). The inclusion of phytase linearly increased fecal pH, concentrations of acetic and propionic acids, and total production of short-chain fatty acids (P < 0.05) in the feces of the dogs. Dogs fed the diet with enzyme complex (PD + PC) had a greater intake ratio when compared to the PD diet (P < 0.05). There was no difference (P > 0.05) in the first choice of the dogs for a specific diet for any of the comparisons made. Enzyme supplementation did not influence nutrient digestibility, but it increased the ME content of the PD. In addition, supplementation with the carbohydrase complex increased the production of total short-chain fatty acids and reduced fecal dry matter without compromising the acceptance of the diets.

Life Cycle Assessment of Total Fatty Acid (TFA) Production from Microalgae Nannochloropsis oceanica at Different Sites and Under Different Sustainability Scenarios

The environmental sustainability of the microalgae Nannochloropsis oceanica cultivation for total fatty acid (TFA) production was analyzed using life cycle assessment (LCA). Pilot data provided by the plant operator from cultivation in Italy using Green Wall Panel (GWP®) photobioreactors were upscaled to a 20-ha production process, and an LCA was conducted and assessed for the Italian regions of Tuscany and Sicily. Two additional scenarios were modelled to analyze the influence of more sustainable framework conditions, respectively nutrient recycling and renewable energy supply. The results show that environmental impacts per functional unit are around 15% less at the site with optimal growth conditions. Between 60 and 80% of the impacts are due to the energy demand during plant operation, infrastructure, and nutrient demand. Nutrient recycling and the gain of an energy credit from the separated biocrude with the hydrothermal liquefaction (HTL) process reduce the environmental impacts in all six International Reference Life Cycle Data System (ILCD) impact categories by an average of 11% compared to a scenario without nutrient recycling. The additional consideration of a renewable energy supply allows for an average reduction of 36% and together with the nutrient recycling of an average of 45% for the global warming potential (GWP) and most of the other impact categories.

Main active components of Jiawei Gegen Qinlian decoction protects against ulcerative colitis under different dietary environments in a gut microbiota-dependent manner

As an effective drug against acute enteritis diarrhea, Gegen Qinlian decoction (GQD) has a history of 2000 years. However, the potential molecular mechanism through which GQD could protect intestinal barrier from ulcerative colitis (UC) still remains undefined. As an important part of the homeostasis of the colon, gut microbiota is closely related to the dynamic evolution of the surrounding environment and the adjustment of dietary structure. At present, the effectiveness and mechanism of Jiawei Gegen Qinlian decoction against UC in different dietary environments are not clear. Here, the main active components of Jiawei Gegen Qinlian Decoction (PBM), were selected to construct a reasonable and effective compound scheme. We adopted "5% dextran sulfate sodium (DSS)" and "high temperature and humidity + high sugar and high fat + alcohol + 5%DSS" to induce UC rat models in general environment and UC rat models in Lingnan area, respectively. Then, we examined the therapeutic effects of PBM (89.96 mg/kg and 179.92 mg/kg) on two kinds of UC rats. The role of gut microbiota in the anti-UC effect of PBM was identified by intestinal flora consumption and fecal microbiota transplantation (FMT) experiments. Subsequently, we monitored the alterations of gut microbiota and fecal metabolism in the rat colon by 16Sr DNA technique and targeted metabonomics, respectively. The colon inflammation of the PBM-treated and the FMT-treated rats both showed significant relief, as evidenced by a reduction in body weight loss, bloody stool, diarrhea, disease activity index (DAI) score, shortening of colon length as well as decreased colon histology damage. Interestingly enough, the depletion of intestinal flora took away the protective effect of PBM, confirming the importance of intestinal flora in the anti-UC effect of PBM. Then our findings suggested that PBM could not only regulate the gut microbiota by increasing Akkermansia and Romboutsia but also decrease Escherichia-Shigella. More importantly, PBM could increase the production of propionate and total short-chain fatty acids (SCFAs) in colitis rats, regulate medium and long chain fatty acids (M-LCFAs), maintain bile acids (BAs) homeostasis, and regulate amino acids (AAs) metabolism. The transformation of intestinal environment might be related to the upregulation of anti-inflammation, anti-oxidation and tight junction protein expression in colonic mucosa. In summary, PBM showed potential for anti-UC activity through gut microbiota dependence and was expected to be a complementary and alternative medicine herb therapy.

The Efficacy of Plant-Based Bioactives Supplementation to Different Proportion of Concentrate Diets on Methane Production and Rumen Fermentation Characteristics In Vitro.

Simple SummaryUsing natural feed additives to mitigate methane emissions from ruminants is a promising strategy. Many antimethanogenic compounds have been used to alter rumen fermentation, yet their potential to reduce methane production effectively is not consistent across different kinds of feeding styles (forage:concentrate ratios). Consequently, in the current study we investigated the efficacy of plant-bioactives extract (PE) (a novel phytogenic mixture of garlic and citrus extracts) on rumen fermentation characteristics and methane production in different kinds of feeding styles. The current In Vitro study showed that PE was effective in reducing methane production in all feeding styles without exhibiting any adverse effect on nutrient digestibility. Furthermore, PE supplementation was able to improve the rumen fermentation through increasing the production of total volatile fatty acids. Therefore, PE mixture could be used as a dietary supplement to reduce the methane production from ruminants. This In Vitro study was conducted to investigate the impact of plant-bioactives extract (PE), a combination of garlic powder and bitter orange extract, on methane production, rumen fermentation, and digestibility in different feeding models. The dietary treatments were 1000 g grass/kg ration + 0 g concentrate/kg ration (100:0), 80:20, 60:40, 40:60, and 20:80. The PE was supplemented at 200 g/kg of the feed. Each group consisted of 6 replicates. The experiment was performed as an In Vitro batch culture for 24 h at 39 °C. This procedure was repeated in three consecutive runs. The results of this experiment showed that supplementation with PE strongly reduced methane production in all kinds of feeding models (p < 0.001). Its efficacy in reducing methane/digestible dry matter was 44% in the 100:0 diet, and this reduction power increased up to a 69.2% with the inclusion of concentrate in the 20:80 diet. The PE application significantly increased gas and carbon dioxide production and the concentration of ammonia-nitrogen, but decreased the pH (p < 0.001). In contrast, it did not interfere with organic matter and fiber digestibility. Supplementation with PE was effective in altering rumen fermentation toward less acetate and more propionate and butyrate (p < 0.001). Additionally, it improved the production of total volatile fatty acids in all feeding models (p < 0.001). In conclusion, the PE combination showed effective methane reduction by improving rumen fermentation characteristics without exhibiting adverse effects on fiber digestibility. Thus, PE could be used with all kinds of feeding models to effectively mitigate methane emissions from ruminants.

Understanding and exploiting the fatty acid desaturation system in Rhodotorula toruloides

BackgroundRhodotorula toruloides is a robust producer of triacylglycerol owing to its fast growth rate and strong metabolic flux under conditions of high cell density fermentation. However, the molecular basis of fatty acid biosynthesis, desaturation and regulation remains elusive.ResultsWe present the molecular characterization of four fatty acid desaturase (FAD) genes in R. toruloides. Biosynthesis of oleic acid (OA) and palmitoleic acid (POA) was conferred by a single-copy ∆9 Fad (Ole1) as targeted deletion of which abolished the biosynthesis of all unsaturated fatty acids. Conversion of OA to linoleic acid (LA) and α-linolenic acid (ALA) was predominantly catalyzed by the bifunctional ∆12/∆15 Fad2. FAD4 was found to encode a trifunctional ∆9/∆12/∆15 FAD, playing important roles in lipid and biomass production as well as stress resistance. Furthermore, an abundantly transcribed OLE1-related gene, OLE2 encoding a 149-aa protein, was shown to regulate Ole1 regioselectivity. Like other fungi, the transcription of FAD genes was controlled by nitrogen levels and fatty acids in the medium. A conserved DNA motif, (T/C)(G/A)TTGCAGA(T/C)CCCAG, was demonstrated to mediate the transcription of OLE1 by POA/OA. The applications of these FAD genes were illustrated by engineering high-level production of OA and γ-linolenic acid (GLA).ConclusionOur work has gained novel insights on the transcriptional regulation of FAD genes, evolution of FAD enzymes and their roles in UFA biosynthesis, membrane stress resistance and, cell mass and total fatty acid production. Our findings should illuminate fatty acid metabolic engineering in R. toruloides and beyond.

Carbonate assisted lipid extraction and biodiesel production from wet microalgal biomass and recycling waste carbonate for CO2 supply in microalgae cultivation

High cost of microalgal biofuel is caused by all the steps in current technology, including cultivation, harvesting, lipid extraction, biofuel processing and wastewater and waste treatment. This study aims to systematically reduce these costs with one integrated process, in which carbonate is used for cell rupture, lipid extraction and biodiesel processing, and then recycled for CO2 absorption and carbon supply for a new round of algae cultivation. To reach this goal, carbonate-heating treatment with N, N' - dibutylurea which can enhance cell disruption were used for cell-wall breaking of wet Neochloris oleoabundans (UTEX 1185) biomass. Lipid extraction was fulfilled with carbonate/ethanol aqueous two phase extraction method and residual carbonate with wastewater from bottom phase was recycled to absorb CO2 to generate bicarbonate for algal cultivation with fresh medium. Taking into comprehensive consideration of cell disruption efficiency, partition coefficient, and lipid recovery, the condition of cell disruption and lipid extraction was set at 90°C, 100min reaction time, 1:7.5 DBU:H2O (w/w) ratio, 1:3 Na2CO3:H2O (w/w) ratio, and 9% (w/wT) ethanol concentration. The results showed that carbonate-heating treatment of wet N. oleoabundans biomass resulted in up to 90.7% cell disruption efficiency. The lipid recovery rate in carbonate/ethanol system was up to 97.9%, and the final biodiesel production was 1.30 times of that with Soxhlet method. Utilization of the waste broth after CO2 absorption with the content of 4% (v/vT) in the medium for new batch of algae cultivation resulted in biomass concentration of 1.68g/L. The corresponding total fatty acids production was 0.35g/L, which was 1.63 fold of that with fresh medium. This study firstly proved the feasibility of using carbonate for lipid extraction and biodiesel production and recycle waste carbonate for carbon re-supply during algae cultivation.

Pigment and Fatty Acid Production under Different Light Qualities in the Diatom Phaeodactylum tricornutum

Diatoms are microscopic biorefineries producing value-added molecules, including unique pigments, triglycerides (TAGs) and long-chain polyunsaturated fatty acids (LC-PUFAs), with potential implications in aquaculture feeding and the food or biofuel industries. These molecules are utilized in vivo for energy harvesting from sunlight to drive photosynthesis and as photosynthetic storage products, respectively. In the present paper, we evaluate the effect of narrow-band spectral illumination on carotenoid, LC-PUFAs and TAG contents in the model diatom Phaeodactylum tricornutum. Shorter wavelengths in the blue spectral range resulted in higher production of total fatty acids, namely saturated TAGs. Longer wavelengths in the red spectral range increased the cell’s content in Hexadecatrienoic acid (HTA) and Eicosapentaenoic acid (EPA). Red wavelengths induced higher production of photoprotective carotenoids, namely fucoxanthin. In combination, the results demonstrate how diatom value-added molecule production can be modulated by spectral light control during the growth. How diatoms could use such mechanisms to regulate efficient light absorption and cell buoyancy in the open ocean is discussed.

Developing microalgal oil production for an outdoor photobioreactor

In this paper the preparations are described to develop a production of oil rich microalgal biomass under south European conditions. Ten microalgal species were compared in shake flasks in an incubator for potential for oil production. Potential oil production capacity was assayed as maximum total fatty acid (TFA) concentration and volumetric TFA productivity. TFA concentration ranged from 5 to 40% DW while TFA productivity rate ranged from 0 to 204 mg TFA L−1 day−1. To control the oil enrichment process in the outdoor microalgal batch culture, a quadratic equation was proposed, predicting the TFA concentration based on biomass inverse nitrogen quota. A concentrated substrate was developed to add to sea water, made from natural sea-salt and tap water.

Bioconversion of food waste to volatile fatty acids: Impact of microbial community, pH and retention time

Bio-based production of materials from waste streams is a pivotal aspect in a circular economy. This study aimed to investigate the influence of inoculum (three different sludge taken from anaerobic digestors), pH (5 & 10) and retention time on production of total volatile fatty acids (VFAs), VFA composition as well as the microbial community during anaerobic digestion of food waste. The highest VFA production was ∼22000 ± 1036 mg COD/L and 12927 ± 1029 mg COD/L on day 15 using the inoculum acclimated to food waste at pH 10 and pH 5, respectively. Acetic acid was the dominant VFA in the batch reactors with initial alkaline conditions, whereas both propionic and acetic acids were the dominant products in the acidic condition. Firmicutes, Chloroflexi and Bacteroidetes had the highest relative abundance in the reactors. VFA generation was positively correlated to the relative abundance of Firmicutes.

Impacts of Mootral on Methane Production, Rumen Fermentation, and Microbial Community in an in vitro Study.

Methane mitigation strategies have a two-sided benefit for both environment and efficient livestock production. This preliminary short-term in vitro trial using Mootral (garlic and citrus extracts), a novel natural feed supplement, was conducted to evaluate its efficacy on rumen fermentation characteristics, methane production, and the bacterial and archaeal community. The experiment was performed as a batch culture using rumen fluid collected from sheep, and Mootral was supplemented in three concentrations: 0% (Control), 10%, and 20% of the substrate (50% Grass:50% Concentrate). The rumen fermentation data and alpha diversity of microbial community were analyzed by ordinary one-way analysis of variance. The relative abundance and statistical significance of families and operational taxonomic units (OTUs) among the groups were compared by Kruskal–Wallis H test using Calypso software. After 24-h incubation at 39°C, Mootral in a dose-dependent manner improved the production of total volatile fatty acids and propionate while it reduced the acetate proportion and acetate/propionate ratio. The total produced gas was two times higher in the Mootral-supplemented groups than control (P < 0.01), while the proportion of methane in the produced gas was reduced by 22% (P < 0.05) and 54% (P < 0.01) for 10 and 20% Mootral, respectively. Mootral did not change pH, digestibility, and ammonia-nitrogen. Microbial community analyses showed that Mootral effectively changed the ruminal microbiome. The bacterial community showed an increase of the relative abundance of the propionate-producing family such as Prevotellaceae (P = 0.014) and Veillonellaceae (P = 0.030), while there was a decrease in the relative abundance of some hydrogen-producing bacteria by Mootral supplementation. In the archaeal community, Methanobacteriaceae was decreased by Mootral supplementation compared with control (P = 0.032), while the Methanomassiliicoccaceae family increased in a dose-dependent effect (P = 0.038). The results of the study showed the efficacy of the new mixture to alter the ruminal microbial community, produce more propionate, and reduce microbial groups associated with methane production, thus suggesting that Mootral is a promising natural mixture for methane reduction from ruminants.

Galactooligosaccharide pretreatment alleviates damage of the intestinal barrier and inflammatory responses in LPS-challenged mice.

Galactooligosaccharides (GOS) have been identified as beneficial prebiotics for animals and human beings. Most studies have focused on the effect of GOS on the hindgut populated with abundant microbes. However, few research studies have been conducted on the small intestine, and many results are inconsistent due to the purity of GOS, commonly mixed with monosaccharides or lactose. Therefore, pure GOS with definite structures were prepared and used in the present study to evaluate their effects on intestinal barrier function, inflammatory responses and short-chain fatty acids (SCFAs) produced in the colon of mice challenged with lipopolysaccharide (LPS). The results of 1H and 13C nuclear magnetic resonance spectral analyses indicated that the main structures of GOS with a degree of polymerization of 3 (trisaccharide) and 4 (tetrasaccharide) are [β-Gal-(1 → 6)-β-Gal(1 → 4)-β-Glc] and [β-Gal-(1 → 6)-β-Gal-(1 → 6)-β-Gal-(1 → 4)-β-Glc], respectively. The results of an in vivo study in mice showed that intragastric administration of 0.5 g per kg BW GOS attenuated intestinal barrier damage and inflammatory responses induced by LPS in the jejunum and ileum, as indicated by increasing villus height and villus-to-crypt ratio, up-regulated intestinal tight junction (ZO-1, occludin, and claudin-1) gene expression, and down-regulated pro-inflammatory cytokines such as IL-1β, IL-6, IFN-γ, and TNF-α gene expression. Nevertheless, the protective effects of GOS on the intestinal barrier are independent of glucagon-like peptide 2. In addition, 0.5 g per kg BW GOS administration promoted the recovery of colonic acetate, propionate, butyrate, and total SCFA production reduced by LPS challenge. The obtained results provide practical evidence that pure GOS can act as protective agents for intestinal health.