Lipid production by oleaginous microorganisms using food wastes: a review / 生物工程学报

Food wastes are rich in nutrients and can be used for producing useful chemicals through biotransformation. Some oleaginous microorganisms can use food wastes to produce lipids and high value-added metabolites such as polyunsaturated fatty acids, squalene, and carotenoids. This not only reduces the production cost, but also improves the economic value of the products, thus has large potential for commercial production. This review summarized the advances in food waste treatment, with a focus on the lipid production by oleaginous microorganisms using food wastes. Moreover, challenges and future directions were prospected with the aim to provide a useful reference for related researchers.

Obtaining, characterization and evaluation of two candidate preparations for probiotics developed with agroindustrial waste / Obtención, caracterización y evaluación de dos preparados candidatos a probióticos desarrollados con residuos agroindustriales

ABSTRACT Objective. Obtain, characterize and evaluate two bio-prepares developed from the sugar cane molasses - orange vinasse fermented with yeast and/or lactic acid bacteria. Materials and methods. A completely randomized design was used, with five repeats per treatment. The evaluated treatments were: T1, Lactobacillus acidophilus, Lactobacillus bulgaricus, Streptococcus thermophilus y T2, the previous bacteria plus Saccharomyces cerevisiae and Kluyveromyces fragilis (L-4 UCLV). The previous mentioned microorganisms were inoculated in a substratum compounded by molasses - vinasse and these were incubated at 37°C for 24 hours. To the bioprepares, physiochemical, microbiological and in vitro tests was made to evaluate the probiotic capacity. Results. Both bioprepares presented a dark brown color, sweet and a pH lesser than 4. The bromatological and microbiologic development were higher (p>0.05) in T2. Both bioprepares the viability was higher than 92%. in vitro tests two bioprepares were resistant to an acid pH, bile salts, broad spectrum of microbial activity and inhibitory effect to E. coli, Salmonella spp. and S. aureus. Conclusions. The bioprepares obtained from sugar cane molasses - orange vinasse fermented with yeast and lactic acid bacteria manifested physiochemical and microbiologic properties appropriated to probiotic products. In in vitro tests, their potential was demonstrated as a probiotic.

RESUMEN Objetivo. Obtener, caracterizar y evaluar dos biopreparados desarrollados a partir de melaza de caña de azúcar - vinaza de naranja fermentados con levaduras y/o bacterias ácido lácticas. Materiales y métodos. Se utilizó un diseño completamente aleatorizado con cinco repeticiones por tratamiento. Los tratamientos evaluados fueron: T1, Lactobacillus acidophilus, Lactobacillus bulgaricus, Streptococcus thermophilus y T2, las bacterias anteriores más Saccharomyces cerevisiae y Kluyveromyces fragilis (L-4 UCLV). En un sustrato compuesto por melaza- vinaza se inocularon los microorganismos anteriormente mencionados y estos fueron incubados a 37ºC por 24 h. Se les determinaron a los biopreparados los parámetros fisicoquímicos, microbiológico y se realizaron las pruebas in vitro para evaluar la capacidad probiótica. Resultados. Ambos biopreparados presentaron un color marrón oscuro, dulzón y con pH inferior a 4. El comportamiento bromatológicos y microbiológicos fueron mayores (p>0.05) en el T2. En ambos biopreparados la viabilidad fue superior a 92%. En pruebas in vitro, ambos biopreparados fueron resistentes a pH ácido, sales biliares, amplio espectro de actividad antimicrobiana y efecto inhibitorio a la E. coli, Salmonella spp. y S. aureus. Conclusiones. Los biopreparados obtenidos a partir de melaza de caña de azúcar-vinaza de naranja fermentados con levaduras y/o bacterias ácido lácticas demostraron propiedades físicoquímicas, microbiológicas apropiadas para productos probióticos. En las pruebas in vitro, se demostró su efecto potencial como probiótico.

Formulación mixta de bacterias lácticas para el control de Listeria monocytogenes / Mixted formulation of lactic bacterium for the control of Listeria monocytogenes

Resumen La combinación de la actividad metabólica de cepas bacterianas potencializa la actividad antimicrobiana contra microorganismos patógenos, en comparación con la actividad que pueden presentar las cepas microbianas en forma individual. La formulación mixta de bacterias acido lácticas ha sido estudiada para la producción de preparados probióticos con actividad antimicrobiana contra patógenos. Listeria monocytogenes es considerado un microorganismo patógeno para el hombre y animales, causando principalmente, la enfermedad conocida como listeriosis. Se evaluó la actividad antimicrobiana de una formulación mixta de Lactobacillus brevis y Weisella cibaria frente a Listeria monocytogenes. L. brevis y W. cibaria se reprodujeron por fermentaciones en discontinuo durante 48 horas. Se midió la cinética de la actividad antimicrobiana contra L. monocytogenes en los siguientes tiempos de fermentación, 0, 1, 2, 6, 12, 24 y 48 horas. En cada tiempo, la actividad antimicrobiana de la mezcla de cepas se comparó con la actividad antimicrobiana de las cepas en forma individual. La actividad antimicrobiana se midió mediante el diámetro de Feret, utilizando un software de evaluación de imágenes. Se encontró que la actividad antimicrobiana de la mezcla de cepas contra L. monocytogenes fue estable desde la segunda hora de fermentación hasta las 48 horas. A partir de 18 horas de fermentación la mezcla de cepas presentó actividad antimicrobiana superior, comparada con las cepas individuales. Los resultados indican que la formulación mixta de L. brevis y W. cibaria podría ser una opción biotecnológica para el desarrollo de antimicrobianos naturales para el control y prevención de L. monocytogenes.

Abstract The combination of the metabolic activity of bacterial strains potentiates the antimicrobial activity against pathogenic microorganisms, in comparison with the activity that the microbial strains can present individually. The mixed formulation of lactic acid bacteria has been studied to the production of probiotic preparations with antimicrobial activity against pathogens. Listeria monocytogenes is considered a pathogenic microorganism for man and animals, causing the disease known as listeriosis. The antimicrobial activity of a mixed formulation of Lactobacillus brevis and Weisella cibaria was evaluated against Listeria monocytogenes. L. brevis and W. cibaria were reproduced by discontinuous fermentations for 48 hours. The kinetics of antimicrobial activity against L. monocytogenes were measured at the next fermentation times, 0, 1, 2, 6, 12, 24 and 48 hours. At each time, the antimicrobial activity of the mixed formulation was compared with the antimicrobial activity of the strains individually. The antimicrobial activity was measured by Feret's diameter, using image evaluation software. It was found that the antimicrobial activity of the mixed formulation against L. monocytogenes was stable from the second hour of fermentation to 48 hours of fermentation. After 18 hours of fermentation the mixed formulation presented superior antimicrobial activity, compared to the individual strains. The results indicate that the mixed formulation of L. brevis and W. cibaria could be a biotechnological option for the development of natural antimicrobials for the control and prevention of L. monocytogenes.

Fitness analysis between the L-sorbosone dehydrogenase modules and Ketogulonigenium vulgare chassis / 生物工程学报

Ketogulonigenium vulgare is an acid-producing strain in the process of two-step vitamin C fermentation. L-sorbosone dehydrogenase (SNDH) is one of the key enzymes during the biosynthesis of 2-keto-L-gulonic acid (2-KGA), the precursor of vitamin C. However, the catalytic mechanism of SNDH is unclear. According to the whole genome sequencing of K. vulgare, two genes encoding sorbosone dehydrogenases, one derived from the chromosome (named as sndhg) and one from plasmid (named as sndhp), were introduced into an industrial strain K. vulgare. The overexpression of gene sndhg had hardly effect on 2-KGA production, and the overexpression of gene sndhp produced an obvious byproduct in the fermentation broth. Combinational expression of sndhg/sndhp with pqqA (obtaining sndhg-pqqA and sndhp-pqqA modules) in K. vulgare resulted in the similar fermentation phenotype to two previous strains. After serial sub-cultivation of co-cultured Bacillus endophyticus with each engineered K. vulgare for 50 d, the conversion rate of 2-KGA increased by 15.4%, 179%, 0.65% and 125% compared with that of the parental K. vulgare with B. endophyticus. This study shows that adaptive evolution of microbial consortium is an effective strategy to increase the fitness between functional modules and chassis, thus quickly getting better strains for production of 2-KGA.

Mixed Cultures Fermentation for the Production of Poly- ß-hydroxybutyrate

Poly-ß-hydroxybutyrate (PHB) is a biodegradable intracellular microbial product produced by many bacteria and it is comparable to some of the petrochemical derived thermoplastics such as polypropylene. One of the main barriers for the commercial exploitation is the high cost of the substrate for the production of biopolymer. The utilization of mixed microbial cultures facilitates the use of complex substrates thereby reducing the cost of PHB production. In the present study, mixed culture systems were evaluated for PHB production. Bacillus firmus NII 0830 was used for the production of PHB since it accumulates a large amount of PHB and a second organism Lactobacillus delbrueckii NII 0925 was used to provide lactic acid. FTIR and 1H NMR analyses revealed that the PHB extracted from pure culture and mixed culture showed exact match to that of standard PHB. Biodegradation studies of the PHB blends showed 87% degradation. It was also found that a consortium of organisms degraded the films faster than a single organism.

The effect of Candida albicans and Bacterial Mixed Culture on C. albicans / 대한의진균학회지

BACKGROUND: Fungal-bacterial interactions are ubiquitous. Implanted medical devices, including urinary bladder catheters, are particularly susceptible to colonization by Candida spp. and opportunistic bacterial pathogens. Less is known about the fungal side of fungal-bacterial interactions. OBJECTIVE: The aim of the present study was to evaluate the effect of mixed culture on C. albicans and bacteria. METHODS: After C. albicans was incubated either alone or in mixed culture with bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, Staphylococcus aureus, S. epidermidis, Enterococcus faecalis, and E. faecium) in blood agar plate, colony count and diameter were read. Minimum inhibitory concentration (MIC) of C. albicans to fluconazole, itraconazole, and voriconazole were tested by broth microdilution method of the Clinical and Laboratory Standards Institute (CLSI) M27-A3. The expression of target gene (ERG11) was analyzed by RT-PCR using real-time PCR system. RESULTS: When C. albicans and P. aeruginosa were mixed cultured, the colony count of C. albicans significantly decreased (p=0.021). The colony size, MIC, and ERG11 mRNA expression were no significant differences between single and mixed culture. CONCLUSIONS: Further investigations are warranted to understand the fungal-bacterial interaction in order to aid in the design of new strategies for the treatment and prevention of infections.

Biodegradation of Benzo[a]pyrene by the mixed culture of Bacillus cereus and Bacillus vireti isolated from the petrochemical industry.

Polycyclic aromatic hydrocarbons are a group of compounds that pose threat to humans and animal life. Methods to reduce the amount of PAHs in the environment are continuously being sought. The bacterial consortium capable of utilizing benzo(a)pyrene as the sole source of carbon and energy was isolated from petrochemical soil. The isolates were identified as Bacillus cereus and Bacillus vireti based on morphological characterization, and 16S rDNA gene sequence analysis. About 58.98 % of benzo(a)pyrene at concentration of 500 mg l-1 in mineral salts medium were removed by bacterial consortium. GC mass spectral analysis showed the presence of metabolite cis-4-(7-hydroxypyren-8-yl)-2-oxobut-3enoic acid. The results indicate that the bacterial consortium is a new bacterial resource for biodegrading benzo(a)pyrene and might be used for bioremediation of sites heavily contaminated by benzo[a]pyrene and its derivatives.

Biodegradation of oil refinery residues using mixed-culture of microorganisms isolated from a landfarming

In this study, the potential for using an inoculum composed of a mixed-culture of bacteria and fungi, isolated from a landfarming at the Paulínia Oil Refinery, Brazil, to degrade oil residues generated in the process of petroleum refinement was investigated. The isolation of these microorganisms was carried out beforehand, assuming that they would be better adapted to petroleum hydrocarbons, as the landfarming consisted of an area impacted by the deposit of such compounds. The Bartha and Pramer respirometric test was used to measure the rate of biodegradation of the hydrocarbons by the mixed-culture of microorganisms via the evolution of CO2. The results obtained with respect to the efficiency of biodegradation showed no significant differences (P>0.05), indicating no increase in the biodegradation process using the inoculum. The addition of nutrients (N, P, K) also did not contribute to an increase in biodegradation of the oil residue studied.

Neste estudo foi investigado o potencial de um inóculo composto de cultura mista de bactérias e fungos, isolados do landfarming da Refinaria de Paulínia, Brasil, em degradar resíduos oleosos gerados no processo de refinamento de petróleo. O isolamento desses microrganismos foi realizado previamente, supondo-se que estejam melhor adaptados aos hidrocarbonetos de petróleo uma vez que o landfarming consiste em área impactada por deposição de tais compostos. Utilizou-se o teste respirométrico de Bartha e Pramer no intuito de verificar a taxa de biodegradação dos hidrocarbonetos pela cultura mista de microrganismos através da evolução de CO2. Os resultados obtidos para a eficiência da biodegradação não apresentaram diferença estatisticamente significativa (P>0.05) indicando que não houve aumento do processo de biodegradação com o uso do inóculo. A adição de nutrientes (N, P, K) tampouco contribuiu para aumentar a biodegradação do resíduo oleoso estudado.

Analysis of Sponge-associated Culturable and Natural Microbial Community Structure Based on DGGE Fingerprinting / 微生物学通报

The microbial community structure of 4 kinds of sponges in South China Sea were revealed using culture-independent PCR- DGGE gene fingerprint technique as well as the mixed culturable microorganism. The relationship between the culturable and un-culturable microorganism was studied based on the different fingerprint profile. It was found that there is host specificity for microorganism in different sponges from the same marine area. Culture condition such as medium is an important factor for sponge-associated microbial cultivation and the culturable microorganism amount to only a little part of the total sponge-associated microorganisms.

STUDY ON THE FERMENTATION CONDITION PRODUCING 2-KETO-LGLUCONIC ACID BY USING MIXED CULTURE OF MICROORGANISM / 微生物学通报

Vitamin C precusor-2-keto-L-gulonic acid can be prepared directly by mixed culture of Ghiconobacter oxy-dans SCB329 and Guconobacter subaxydans SCB110. To obtained its high yield, firstly, the proportion of the two micro- organisms, the ingredients of medium and the initial pH were optimized in shake flaskd, then L9 (34) orthogonal experiment confirmed that urea, C. S. L had high degree statistical meaning. Based on these data, an optimized fermentation media was obta ined: D-Sorbitol 9g, C. S.L1.5g, Urea1.5g, KH2PO40.1g, CaCO30.2g. By-product can be inhabited to the greatest extent and the yield increases by 20%.

Stable Coexistence of Five Bacterial Strains as a Community in an Immobilized Continuous Culture System / 微生物学通报

Five kinds of probiotic bacteria are immobilized and cultured continuously in simulated intestinal systems with corn fiber as the carrier.The biomass and the colonization in biofilm are investigated by selective culture methods and scanning electron microscope.Bifidobacteriurn longum TQ21-2-2,Lactobacillus acidophile CICC06005,Clostridum butyric TO-A,Bacillus mesentericus TO-A and Enterococcus faecalis T-110 can coexist stably.The biomass of five probiotics in the immobilized phase is greater than that of liquid in the continuous shake flask reactor.Five kinds of probiotic bacteria formed biofilm on corn fiber which be observed by SEM.Continuous culture of immobilized cells could be used better model than that of liquid, the model can be used to study for microecology and microecologocal agent.

ENGLISH ABSTRACTS OF ORIGINAL ARTICLES Effect of Mixed Cord Blood Culture on CFU-GM Yield / 中国输血杂志

The amount of CFU-GM colony and cluster yielded after the two units of cord blood were mixed, was observed,using the in vitro CFU-GM culture technique, indicating that the yield of CFU-GM colony and cluster in the mixed culture group was no less than that in the single culture group, so this study can provide the theoritical basis for the transplantation of mixed cord blood hematopoietic stem cells.