High Acidification Rate Research Articles

Feasibility and mechanism exploration of enhancing short chain fatty acid production assisted by nitrate photolysis during sludge fermentation

Seeking for the eco-friendly and low-cost pretreatment technology has become the prerequisite for the efficient release of the embedded organics in waste activated sludge (WAS), further for the higher production of short chain fatty acids (SCFAs) via anaerobic fermentation. Nitrate, which can produce reactive oxygen species (ROS) and reactive nitrogen species (RNS) during photolysis, may have the positive effect on WAS disintegration and organics degradation, while its performance and mechanism for WAS treatment is still unknown. This study investigated the feasibility of the nitrate photolysis on WAS disintegration and SCFAs production, and elucidated the underlying mechanism. Results showed that the highest acidification rate (26.6 h−1) and short-chain fatty acid (SCFAs) production (5370.6 mg COD/L) were achieved at 8 d in the nitrate photolysis group (Nitrate-UV) during the anaerobic fermentation, significantly promoted by 2.3 and 12.7 folds than that of Control (raw WAS). Acetic acid (HAc) and propionic acid (HPr) accounted for 89.1 % and 90.1 % in Nitrate-UV and Nitrate group (sole nitrate addition), which were much higher than that obtained in UV and Control. HO• and O2•− were the main contributors compared with NO2•, ONOO– and NO• on the release and bioconversion of the soluble organics. Microbial community and metagenomics revealed the promotion of nitrate photolysis on anaerobic fermentation bacteria (AFB) and nitrate reducing bacteria (NRB), as well as the gene abundance related to the metabolic pathways of glycolysis, amino acid, acetate and nitrogen metabolism, which jointly devoted to the SCFAs enhancement during the anaerobic fermentation.

Study on the Effect of Inoculation of Mixed Inoculation on Hydrolysis and Acidification Performance of Kitchen Waste

The effect of a mixture of different inoculants as inoculum on the hydrolytic and acidification process was investigated in order to improve the hydrolytic and acidification properties of kitchen waste. The results showed that the inoculation of Baijiu pit mud had the feasibility to improve the hydrolytic acidification performance during the hydrolytic acidification process of kitchen waste. At the end of the hydrolytic acidification process, the SCOD of the 1:0, 3:1,1:1, and 1;3 group increased by 55.97%, 48.67%, 30.82% and 7.03%, respectively, compared with that of the 1:0 group; the hydrolysis rate increased by 2.44%, 7.07%, 2.01% and 2.2% compared with that of the 0:1 group. The highest concentration of VFAs was found in the group with 1:3 ratio of Baijiu pit mud and anaerobic sludge, which was 11353.46 mg/L. The highest acidification rate was found in the 1:3 group, which was 68.57%, and 16.14% higher than that in the 1:0 group. The highest concentration of VFAs was found in the group with 1:3 ratio of Baijiu pit mud and anaerobic sludge, which was 11353.46 mg/L. The highest acidification rate was found in the 1:3 group, which was 68.57%, and 16.14% higher than that in the 1:0 group. Inoculation of Baijiu pit mud was able to change the fraction of VFAs during the hydrolytic acidification of kitchen waste. The fermentation type of the hydrolytic acidification system was ethanol-type fermentation, and the ethanol concentration was increased by 8.64, 8.59, 7.36, and 2.81 times in the groups with the ratio of Baijiu pit mud to anaerobic sludge of 1:0, 3:1, and 1:1, respectively. However, in the Baijiu pit mud and anaerobic sludge ratio of 1:3 and 0:1 group, the main type of fermentation was acetic acid type fermentation. The experimental groups inoculated with Baijiu pit mud.

Fermentation characteristics and postacidification of yogurt by Streptococcus thermophilus CICC 6038 and Lactobacillus delbrueckii ssp. bulgaricus CICC 6047 at optimal inoculum ratio

This study aimed to investigate the symbiosis between Streptococcus thermophilus CICC 6038 and Lactobacillus delbrueckii ssp. bulgaricus CICC 6047. In addition, the effect of their different inoculum ratios was determined, and comparison experiments of fermentation characteristics and storage stability of milk fermented by their monocultures and cocultures at optimal inoculum ratio were performed. We found the time to obtain pH 4.6 and ΔpH during storage varied among 6 inoculum ratios (1:1, 2:1, 10:1, 19:1, 50:1, 100:1). By the statistical model to evaluate the optimal ratio, the ratio of 19:1 was selected, which exhibited high acidification rate and low postacidification with pH values remaining between 4.2 and 4.4 after a 50-d storage. Among the 3 groups included in our analyses (i.e., the monocultures of S. thermophilus CICC 6038 [St] and Lb. bulgaricus CICC 6047 [Lb] and their cocultures [St+Lb] at 19:1), the coculture group showed higher acidification activity, improved rheological properties, richer typical volatile compounds, more desirable sensor quality after the fermentation process than the other 2 groups. However, the continuous accumulation of acetic acid during storage showed that acetic acid was more highly correlated with postacidification than d-lactic acid for the Lb group and St+Lb group. Our study emphasized the importance of selecting an appropriate bacterial consortium at the optimal inoculum ratio to achieve favorable fermentation performance and enhanced postacidification stability during storage.

Valorisation of Wasted Immature Tomato to Innovative Fermented Functional Foods

In this study, the lactic fermentation of immature tomatoes as a tool for food ingredient production was evaluated as a circular economy-oriented alternative for valorising industrial tomatoes that are unsuitable for processing and which have wasted away in large quantities in the field. Two lactic acid bacteria (LAB) were assessed as starter cultures in an immature tomato pulp fermentation to produce functional food ingredients with probiotic potential. The first trial evaluated the probiotic character of Lactiplantibacillus plantarum (LAB97, isolated from immature tomato microbiota) and Weissella paramesenteroides (C1090, from the INIAV collection) through in vitro gastrointestinal digestion simulation. The results showed that LAB97 and C1090 met the probiotic potential viability criterion by maintaining 6 log10 CFU/mL counts after in vitro simulation. The second trial assessed the LAB starters' fermentative ability. Partially decontaminated (110 °C/2 min) immature tomato pulp was used to prepare the individually inoculated samples (Id: LAB97 and C1090). Non-inoculated samples, both with and without thermal treatment (Id: CTR-TT and CTR-NTT, respectively), were prepared as the controls. Fermentation was undertaken (25 °C, 100 rpm) for 14 days. Throughout storage (0, 24, 48, 72 h, 7, and 14 days), all the samples were tested for LAB and Y&M counts, titratable acidity (TA), solid soluble content (SSC), total phenolic content (TPC), antioxidant capacity (AOx), as well as for organic acids and phenolic profiles, and CIELab colour and sensory evaluation (14th day). The LAB growth reached ca. 9 log10 CFU/mL for all samples after 72 h. The LAB97 samples had an earlier and higher acidification rate than the remaining ones, and they were highly correlated to lactic acid increments. The inoculated samples showed a faster and higher decrease rate in their SSC levels when compared to the controls. A nearly two-fold increase (p < 0.05) during the fermentation, over time, was observed in all samples' AOx and TPC (p < 0.05, r = 0.93; similar pattern). The LAB97 samples obtained the best sensory acceptance for flavour and overall appreciation scores when compared to the others. In conclusion, the L. plantarum LAB97 starter culture was selected as a novel probiotic candidate to obtain a potential probiotic ingredient from immature tomato fruits.

Identification, safety and technological characteristics of Weissella strains from traditional Southwestern Algerian kaddid

Kaddid is a dry-fermented meat product traditionally produced in North Africa by spontaneous fermentation. As a reservoir of natural biodiversity, the identification and relevant traits of lactic acid bacteria (LAB) were carried out from South-western Algeria homemade samples. After a preliminary physiological and biochemical screening, 19 presumptive LAB isolates were selected on the basis of antimicrobial compounds production. The isolates were identified by 16S rRNA gene sequencing as Weissella cibaria, W. confusa, W. paramesenteroides, Pediococcusacidilactici, and Enterococcus hirae. As predominant, the safety and technological characterization of Weissella strains were performed. The production of antimicrobial and antifungal compounds was observed, while neither H2S, biogenic amines nor hemolytic activity were detected; antibiotic resistance was exhibited, however several strains were more susceptible to assayed antibiotics. Technological characterization of Weissella strains showed high acidification rates even in the presence of up to 10 % NaCl, autolytic and proteolytic capacity however, no EPS production and lipolytic activity were observed. Strains characterization led to the selection of W. cibaria BK2, W. confusa BK6 and BK11 as well as W. paramesenteroides BK8 to be considered as possible candidates for use as starter culture for kaddid fermentation to improve and standardize this traditional meat product.

The ability of probiotic lactic acid bacteria to ferment Egyptian broken rice milk and produce rice-based yoghurt

Lactic acid bacteria (LAB) contribute to the fermentation of non-dairy cereal products such as rice milk and produce economic products like yoghurt and cheese. These bacteria also have a cytotoxicity activity against cancer cells. The current study intends to use Lactobacillus strains to ferment broken rice milk and produce financial yoghurt products, as well as to assess the growth, physicochemical properties alteration, sensory characteristics, and cytotoxicity of final products. This study indicated that the fermentation of broken rice milk for 8 h by Lactiplantibacillus plantarum ATCC 14917 and milk yoghurt cultures were more favorable than by Lc. casei DSM 20011, and L. acidophilus ATCC20552, which gave high viability (8.9 Log CFU/mL), specific growth rate (0.181, and 0.203 h−1) and doubling time (3.83 and 3.41 h), respectively. Also, they dropped in pH values into ranged from 4.2 to 4.4, and increased in total titratable acidity and the acetic and lactic acids contents (0.82 and1.26 mg/L, respectively). The highest acidification rate (Vmax) was 0.006 and 0.007, and pH U/min, the maximum acidification time (Tmax) was 4 h and the time to reach pH 4.6 (Te) was 5 h and 4 h for sample fermented by Lpb. plantarum and milk yoghurt cultures, respectively. Under refrigerated storage at 5 °C, the rice yoghurt seems to get a shelf life of 12 days. The sensory qualities of LAB rice yoghurt were satisfactory, and it was not toxic (safe) on OEC normal cells (IC50 = ranged between 445.9 and 537.9 μg/mL) and cytotoxic on CaCo-2 colon cancer cells (IC50 = ranged between 107.8 and167.8 μg/mL). The yoghurt rice included a lot of vitamin B6 and B1, but not much vitamin B2 or C. As a result, this product is high in nutritional value.

Determination of probiotic and some technological properties of lactic acid bacteria isolated from cheeses sold in the Kilis region, Turkey

Aims: The purpose of this study is to evaluate technological properties and probiotics potential of lactic acid bacteria (LAB) isolated from 15 raw milk Turkish Beyaz fresh cheese made in the Kilis region, Turkey.Methods and Results: 287 colonies from 15 cheese samples were selected and 91 of them were analyzed as Gram-positive and catalase-negative. 19 strains of 91 colonies were accepted as potential probiotics since they stayed alive in pH 3.5 and 0.3% bile salt. They were identified as Lactobacillus sp. (11 strains), Leuconostoc sp. (3 strains), Streptococcus sp. (2 strains), Lactococcus sp. (2 strains), and Enterococcus sp. (1 strain) by biochemical tests and API test kit. It was determined that 19 strains with high acidification rate, 15 strains demonstrated weak proteolytic activity, 3 ones moderate, and 1 strong proteolytic activity. It was determined that 1 of the strains were resistant to chloramphenicol, 2 to tetracycline, and 6 to vancomycin. No strains resistant to penicillin and erythromycin could be detected. In the artificial gastric juice resistance test, although no viability was detected at pH 2.0. But it was determined that the viability values varied between 89.49-111.79% at pH 3.0. Also, these strains showed growth at bile salt. According to plasmid profiles of strains, 13 of 19 potential probiotic strains were determined to have plasmid DNA in the range of 1-5, while other strains were determined to not have plasmid DNA. The molecular sizes of the plasmid DNA of the isolated strains ranged from 2-16 kb.Conclusions: In the research, it was determined that LABs isolated from Turkish white fresh cheese produced in Kilis have probiotic potential and can be used as starters in various fermented foods.Significance and Impact of the Study: According to the results obtained, it was concluded that some strains can be used as probiotic starter culture in cheese production and others can be used for ripening of cheese.

Effect of sturgeon gelatine hydrolysates and epigallocatechin‐3‐gallate mixtures on technological and rheological properties and viability of probiotics for fat‐free set‐type yoghurt

Sturgeon gelatin hydrolysates combined with epigallocatechin‐3‐gallate (SGH + EGCG) were incorporated in fat‐free set‐type yogurt stabilized using sturgeonish (Ysg) or bovine gelatin (Ybg). Sturgeon gelatin hydrolysates in combination with epigallocatechin‐3‐gallate increased yogurts probiotics growth during refrigerated storage. In Ysg with SGH + EGCG at 0.1 g/dL the flow behavior index (n) was decreased, and the values of consistency coefficient (k), complex viscosity (η*), and yield stress (τ0) increased. Ysg and Ybg had higher acidification rates during fermentation compared to control (Yc). However, the higher SGH + EGCG (0.3 g/dL) led to an increased syneresis and weaker hardness. Results indicated the enhanced fermentation rates, textural, and gelation of Ysg with SGH + EGCG at 0.1 g/dL.

Response Curves for Ammonia and Methane Emissions From Stored Liquid Manure Receiving Low Rates of Sulfuric Acid

Addition of sulfuric acid (H2SO4) to liquid dairy manure (slurry) reduces methane (CH4), nitrous oxide (N2O), and ammonia (NH3) emissions. There is interest in understanding how gaseous emissions respond to decreasing rates of acidification, to determine economically optimum application rates. Acidification rates were tested ranging from 0 to 2 g sulfuric acid (H2SO4) L−1 slurry in six meso-scale outdoor storage tanks, each filled with 10.6 m3 slurry and stored for 114 d. Results showed that the rate of acidification for maximum inhibition of CH4 and NH3 emissions varied markedly, whereas N2O reductions were modest. Reductions of CH4 increased with acid rate from 0 to 1.2 g L−1, with no additional response beyond &amp;gt;1.2 g L−1. In contrast to CH4, inhibitions of NH3 showed a linear response across all rates, although reductions were ≤ 30%. Thus, higher acidification rates would be required to achieve greater NH3 emission reductions. Our findings indicate that achieving &amp;gt;85% NH3 emissions reductions would require 4 × more acid than achieving &amp;gt;85% CH4 reductions. Decisions on optimum H2SO4 rates will depend on the need to mitigate CH4 emissions (the primary greenhouse gas emitted from stored liquid manure) or reduce NH3 emissions (which is regulated in some regions). These results will help develop guidelines related to the potential costs and benefits of reducing emissions through acidification.

Impact of sturgeon gelatin hydrolysates (SGH) on physicochemical and microbiological properties of fat-free set-type yogurt

Gelatin was extracted from beluga sturgeon (Huso huso, SG) and the effects of sturgeon gelatin hydrolysates (SGH) on physicochemical, textural, and rheological properties of yogurt during 28 days of refrigerated storage were explored in this study. SGH at 2 g/dL in yogurt showed the best survival of Lactobacillus bulgaricus, Streptococcus thermophilus, and Bifidobacterium lactis. Based on the results, SGH at 1 g/dL significantly decreased the flow behavior index (n) while increasing the values of k (consistency coefficient), complex viscosity (η*), and yield stress (τ0). Dynamic shear rheological properties indicated higher storage modulus (G′), loss modulus (G″), and η* values at all frequency values compared to control (Yc) whereas Ysgh1 g/dL (yogurt with added SG and SGH) had a better solid-like behavior and elastic gel structure. Ysgh had a higher acidification rate during fermentation and water-holding capacity compared to Yc. However, syneresis and hardness increased and decreased at 2 g/dL SGH, respectively. Overall, SGH might be useful as the potential natural ingredients of fat-free set-type yogurt.

Microbial consortia involved in fermented spelt sourdoughs: dynamics and characterization of yeasts and lactic acid bacteria.

This study aims to describe the native microbiota of fermented spelt, taking into consideration both lactic acid bacteria (LAB) and yeasts, for which little data are available. Five samples of commercial spelt flour were subjected to spontaneous fermentation to obtain a type I sourdough. A total of 186 LAB and 174 yeast isolates were selected at different refreshment steps and subjected to further analyses. Within LAB, coccal isolates constituted 78·5% of the total LAB, with the dominance of Pediococcus pentosaceus. Although documented before as a component, this is the first report of a spelt sourdough fermentation dominated by this homofermentative LAB, characterized by a high acidification rate, ability to utilize a wide range of carbon sources and to grow in high osmolarity conditions. Yeast communities resulted in four dominant species, Saccharomyces cerevisiae, Wickerhamomyces anomalus, Pichia fermentans and Clavispora lusitaniae. This study highlights for the first time the biodiversity and dynamics of yeast communities involved in sourdough fermentation of spelt. Compared to commercial baker's yeast, autochthonous W. anomalus, P. fermentans and S. cerevisiae isolates show a good performance, and their use could be an advantage for their acquired adaptation to the environment, providing stability to the fermentation process. SIGNIFICANCE AND IMPACT OF THE STUDY: Nowadays, there is a renewed interest in products based on spelt. This 'ancient grain' is a highly nutritional grain; however, its use is limited to bread-making processes, which are not standardized. The low baking and sensory quality of spelt can be overcome through fermentation processes. However, the autochthonous microbiota of spelt sourdough is poorly known. This study highlights the dynamics of microbial communities involved in sourdough fermentation of spelt and provides the basis for the selection of autochthonous cultures, with the aim of improving the nutritional potential of spelt and its rheology and bread-making properties.

Newly isolated lactic acid bacteria from silage targeting biofilms of foodborne pathogens during milk fermentation

BackgroundRaw milk, meat and plant materials are subjected to high risks of contamination by various pathogenic bacteria and thus their growth prevention is a great challenge in the food industry. Food fermentation by lactic acid bacteria (LAB) besides changing its organoleptic characteristics also helps to eliminate unfavorable microflora and represses growth of pathogens. To the date only few LABs has been reported to exhibit activity against bacteria embedded in the biofilms characterized by extreme resistance to antimicrobials, high exchange rate with resistance genes and represent high risk factor for foodborne disease development.ResultsSix novel LAB strains isolated from the clover silage exhibited pronounced antibacterial activity against biofilm embedded pathogens. We show explicitly that these strains demonstrate high acidification rate, completely repress the growth of E. coli, S. aureus and to a lesser extent P. aeruginosa as well as exhibit appropriate probiotic and milk-fermenting properties. Moreover, in contrast to the approved probiotic strain Lactobacillus plantarum 8PA3, the new isolates were able to efficiently eradicate preformed biofilms of these pathogens and prevent bacterial spreading originating from the biofilm. We suggest these strains as potential additives to the pre-cultures of conventional LAB strains as efficient tools targeting foodborne pathogens in order to prevent food contamination from either seeded raw material or biofilm-fouled equipment.ConclusionsThe AG10 strain identified as L. plantarum demonstrate attractive probiotic and milk fermentation properties as well as high resistance to simulated gastric conditions thus appearing perspective as a starter culture for the prevention of bacterial contamination originating from fouled equipment during milk fermentation.

A polyphasic approach to characterize Weissella cibaria and Weissella confusa strains.

To study Weissella cibaria and Weissella confusa strains, lactic acid bacteria (LAB) members naturally present in food products, but not yet included in Qualified Presumption of Safety (QPS) list of European Food Safety Authority (EFSA). We carried out a comparative genome analysis of 23 sequenced W. cibaria and 7 W. confusa genomes, in parallel with a physiological and functional characterization of several strains previously isolated from sourdough-like maize bran fermentation. The genome analysis revealed the absence of dedicated pathogenicity factors. Some putative virulence genes found in Weissella genomes were also present in other LAB strains, considered safe by EFSA and commonly used as probiotics. The physiological tests carried out on our strains corroborated the genomic results. Moreover, the following functional traits of interest to application in the food sector were identified: the majority of tested strains displayed high acidification rate, high reducing ability, production of exopolysaccharides (EPS), arabinoxylan degradation ability, growth in the presence of fructo-oligosaccharides (FOS), bile and gastric juice tolerance, and antifungal activity. These results provide evidence for the possible use of selected strains of W. cibaria and W. confusa in the food sector. This polyphasic study adds to the body of knowledge on the functional and applicable characteristics of these controversial species of LAB. This knowledge contributes to design new selected cultures included in the QPS list required for food applications.

Enhanced hydrolysis-acidification of high-solids and low-organic-content sludge by biological thermal-alkaline synergism

In this study, a biological thermal-alkaline synergistic system was successfully established to enhance the hydrolysis-acidification efficiency of high-solids and low-organic-content sludge (HS-LOC-S). The results indicated that the highest hydrolysis rate was obtained at pH of 12 (52.62%) leading to the highest production of soluble chemical oxygen demand (SCOD) and soluble protein (SP). The highest acidification rate was observed at pH of 10 (32.15%), leading to the highest production of volatile fatty acids (VFAs). At pH of 10, average sludge size reduced by 24.60%, and the proportion of biodegradable dissolved organic matter (DOM) produced by synergistic system increased by 15.82%, when compared with those of raw sludge. Moreover, results of 16S rRNA clearly validated that the relative abundance of hydrolytic and acidogenic microbes (e.g. Tepidimicrobium, Coprothermobacter) abundantly enriched at pH of 10 (49.88%) was greatly higher than others, which was the main reason for its maximum VFAs accumulation.

Comparison of the acidification activities of commercial starter cultures in camel and bovine milk

Camel milk has been reported to be difficult to ferment due to anti-microbial properties. The present study tested eight commercial starter cultures for their ability to grow in camel milk. All investigated cultures were able to acidify camel milk and reached a final pH at a level similar to what was achieved in bovine milk, but the speed of acidification was generally lower in camel milk. This could be due to inhibitory substances in camel milk or due to reduced availability of nutrients. Experiments using mixtures of camel and bovine milk or supplementation with casein hydrolysates allowed us to distinguish between these possibilities. High acidification rates were obtained in camel milk mixed with bovine milk or supplemented with casein hydrolysate. This demonstrates that the cultures are not inhibited by camel milk and we conclude that the growth rates of these cultures in pure camel milk are limited by the rate of proteolysis.

Volatile fatty acid production dynamics during the acidification of pretreated olive mill wastewater

This study focuses on the dynamics of VFA production from pretreated olive mill wastewater (OMW). Acidogenic anaerobic sequencing batch reactors (AcASBR) were operated with the pretreated OMW at hydraulic retention time (HRT) of 2days and pH of 5,5 for different organic loading rates (OLRs) ranging from 5gCOD/L.d to 40gCOD/L.d. VFA production reached to the highest value of about 27,000mg/L with the increase in the organic load applied (20gCOD/L.d). The highest acidification rate was calculated as 68%. Acetic acid was found to be as the dominant VFA compound for all stage of the study. At steady state, VFA production during a day-cycle period (24th hour) in AcASBR is also monitored, VFA production gradually increased after the 3rd and 6th hours (about 20%) and a rapid increase (about 40%) was observed reaching the maximum at the end of the cycle (24th hour).

Mitochondrial Complex I Inhibition with Iacs-010759 in T-ALL Preclinical Models

Metabolic reprogramming of the key energy-generating pathways has been long recognized as one of the key oncogenic properties of cancer including leukemia. While accelerated glycolysis is considered to be most common feature of tumors, reliance on oxidative phosphorylation (Oxphos) as a major energy source has been reported for various tumor types. IACS-010759 is a novel OxPhos inhibitor(OxPhosi) that blocks cellular respiration through inhibition of complex I (Molina et al., AACR2016 Abstract #335) and considered as validated drug with clinical relevance in AML and solid tumors. Treatment of adult T-ALL remains unsatisfactory, with approximately one-third of patients experience disease relapse, and novel treatment strategies are warranted. In this study, we report pre-clinical activity of IACS-010759 in T-ALL models and characterize a cellular metabolic profile of T-ALL.Analysis of a panel of T-ALL cell lines showed that IACS-010759 significantly reduced viability measured by CTG assay in all cell lines tested (Notch mutant: Pf382, 1301, Jurkat, MOLT-4, P12-Ichikawa and Notch wt: T-ALL1). T-ALL cells displayed high sensitivity pattern to OxPhos inhibition with EC50 between 0,001 and 10 nM at day 5 analyzed by CTG assay (Fig.1). This reduction of cell viability was primarily due to cell cycle arrest demonstrated by reduction in EdU uptake, and moderate induction of apoptosis in selected T-ALL cell lines. In primary T-ALL samples from patients with newly diagnosed or relapsed/refractory ALL (n=2), in vitro 5-day treatment with IACS-010759 reduced viable cell number at EC50 of 13 nM and 45 nM, respectively. In primary human T-ALL PDX xenografts study, daily oral administration of IACS-010759 at 7.5mg/kg/qd was well tolerated, caused significantly reduced circulating leukemia burden and extended median survival duration (Fig.2).The mitochondrial fuel usage that characterizes Oxphos dependency in T-ALL cell line PF382 was analyzed by Mito fuel Test using the Seahorse Bioscience XF96 Analyzer. Among all three energy sources, PF382 depends most on free fatty acids (FA), indicating strong coupling to Oxphos and TCA cycle (Fig.3). Treatment of T-ALL with IACS-010759 had effectively inhibited FA-stimulated mitochondrial respiration indicated by decreased oxygen consumption rates (OCR) (Fig.4A). However, the cells maintain an ability to generate energy via glycolysis, indicated by high extracellular acidification rate (ECAR) in both, control and IACS-treated groups (Fig.4B). Next, mitochondrial function of T-ALL cells (PF382, Jurkat, 1301, P12Ischikawa, MOLT4, TALL1) was investigated using Mito Stress Test in Seahorse Bioscience XF96 Analyzer. IACS-010759 exposure for 2 hrs caused a striking dose-dependent decrease in basal and maximal OCR, reduction of proton leak and ATP production (Fig.5A, B, C), confirmed by the decreased ATP/ADP and NADH/NAD ratios measured by luminescence assays (ADP/ATP Glow assay, NADH/NAD Glow assay), consistent with inhibition of Oxphos.Conclusions:Taken together, these data provide information about metabolic profiling of T-ALL and indicate that Oxphos inhibition constitutes a novel therapeutic approach that targets a unique metabolic vulnerability of T-ALL cells. Further preclinical evaluation of Oxphos inhibitors in T-ALL is warranted. [Display omitted] DisclosuresJabbour:ARIAD: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Novartis: Research Funding; BMS: Consultancy. Konopleva:Calithera: Research Funding; Cellectis: Research Funding.

Acquisition of PrtS in Streptococcus thermophilus is not enough in certain strains to achieve rapid milk acidification

The acquisition of prtS by Streptococcus thermophilus strains allowed hydrolysis of caseins into peptides and then to increase their growth in milk. This leads to faster milk acidification, which is important in dairy industry. However, some strains harboring the same allele of prtS present different acidification rates, which could be explained by a difference in the regulation of prtS expression. We chose two strains with the same allele of prtS (including the same promoter region): one, PB302, is with high acidification rate while the other, PB18O, is without. They exhibited similar growth in M17, but not in milk, where PB302 showed better growth. The expression of prtS and activity of PrtS were lower in PB18O, in the two media tested. We demonstrated that other genes known to be involved in carbon and nitrogen metabolism were overexpressed in PB302. Interestingly, these genes were overexpressed in milk compared to M17. Nearly all these genes possessed a putative CodY-box in their promoter region. Taken together, difference of gene expression detected in PB302 between milk (low-peptide medium) and M17 (rich-peptide medium) and presence of a putative CodY-box is a feature of the transcriptional pattern of CodY-regulated genes. Altogether, our results propose that acquisition of prtS is not enough in certain strains to achieve rapid milk acidification. High transcriptional level of dtpT, amiF, ilvC, ilvB, bcaT, livJ, ackA, codY, and prtS in fast acidifying strain suggests that this transcriptional pattern could be required for fast milk acidification in Streptococcus thermophilus.

Cascade degradation of organic matters in brewery wastewater using a continuous stirred microbial electrochemical reactor and analysis of microbial communities.

A continuous stirred microbial electrochemical reactor (CSMER), comprising of a complete mixing zone (CMZ) and microbial electrochemical zone (MEZ), was used for brewery wastewater treatment. The system realized 75.4 ± 5.7% of TCOD and 64.9 ± 4.9% of TSS when fed with brewery wastewater concomitantly achieving an average maximum power density of 304 ± 31 m W m−2. Cascade utilization of organic matters made the CSMER remove a wider range of substrates compared with a continuous stirred tank reactor (CSTR), in which process 79.1 ± 5.6% of soluble protein and 86.6 ± 2.2% of soluble carbohydrates were degraded by anaerobic digestion in the CMZ and short-chain volatile fatty acids were further decomposed and generated current in the MEZ. Co-existence of fermentative bacteria (Clostridium and Bacteroides, 19.7% and 5.0%), acetogenic bacteria (Syntrophobacter, 20.8%), methanogenic archaea (Methanosaeta and Methanobacterium, 40.3% and 38.4%) and exoelectrogens (Geobacter, 12.4%) as well as a clear spatial distribution and syntrophic interaction among them contributed to the cascade degradation process in CSMER. The CSMER shows great promise for practical wastewater treatment application due to high pre-hydrolysis and acidification rate, high energy recovery and low capital cost.

Selection and characterization of naturally occurring high acidification rate Streptococcus thermophilus strains

Among Streptococcus thermophilus cultures, the principle component of yoghurt and cheese starters, a minority of strains forms the group of ‘H’-strains which show an unusually high acidification rate, grow faster and coagulate milk 3–5 hours earlier than the typical S. thermophilus cultures. A large-scale screening study was performed to select ‘H’-strains of S. thermophilus from more than 100 samples of home-made yoghurt, industrial yoghurt starters and single cultures, maintained in the LBB culture collection. Only four strains – LBB.TN1, LBB.M23, LBB.M34 and LBB.M60 – were isolated/selected due to their ability to form large yellowish colonies on milk agar, supplemented with beta-glycerophosphate and bromocresol purple. While in general S. thermophilus is described as a species with limited proteolytic capacity and in contrast to all other tested S. thermophilus cultures, the four selected strains invariably gave positive amplification product with the polymerase chain reaction when primers, specific for the membrane proteinase-coding gene prtS were used. The macrorestriction profiles of the genomic DNA of the four strains confirmed that they are non-isogenic and not related to each other. When grown in milk and compared to the control industrial strain LBB.A, the four strains showed a dramatically faster acidification, coagulating milk within four hours. The application of strain TN1 or M23 as adjunct culture to industrial yoghurt starter LBB.BY5-12 resulted in shortening the fermentation time with more than 30 min.