Development of growth medium from meat processing waste products and assessment of its properties

New growth medium based on inedible substrate - meat processing waste products of slaughterhouses - was developed. New medium was characterized by physical, chemical, and biological properties using exacting and non-exacting microorganisms, as well as by periodical cultivation of Corynebacterium diphtheriae strain and obtaining the preparation of its antigens. The experimental medium provided the growth of chosen test-strains with typical properties. From biomass obtained during the periodic cultivation of model toxigenic strain of C. diphtheriae on liquid experimental growth medium, preparation with antigenic properties was extracted. It has been shown that biologic characteristics of experimental growth medium did not differ from those of meat-peptone medium that allows to use it for cultivation of bacteria from various taxonomic groups.     

Properties of Corynebacterium diphtheriae cultivated in the medium prepared from inedible raw materials

A nutrient medium for the cultivation of C. diphtheriae toxigenic strain was developed on the basis of raw materials unsuitable for use as foodstuffs and its main physico-chemical and cultivation properties were studied. The morphological, cultural, biochemical and toxigenic properties of C. diphtheriae cultivated in the experimental medium with horse serum were evaluated. As revealed in this study, C. diphtheriae retained their properties after prolonged cultivation and storage in the newly developed medium, both liquid and with agar added. The medium has a number of advantages: it is economical, raw materials for its production are readily available, the medium is free of ballast substances.     

Effect of magnesium concentration in the culture medium on the trace element requirement of yeasts]

The effect of different magnesium concentrations in the culture liquid (ranging from 2=6 to 220 mg/l) on the accumulation of Mg and Mn ions in the yeast Candida guilliermondii was studied during their continuous cultivation on purified liquid paraffins. A reverse correlation between the accumulation of magnesium and manganese in the yeast biomass was established. The magnesium content in the biomass increased with an increase of its concentration in the nutrient medium. The biomass yield was optimal at a concentration of magnesium ions in the nutrient medium of 10=25 mg/l. Under these conditions the content of magnesium ions was 0.4 mg % and that of manganese ions (upon their concentration in the nutrient medium of 1=2 mg/l) was 20 mg%.     

Mutants of Corynebacterium diphtheriae PW8 that produce toxin in medium with excess iron.

Two mutants that produce toxin in medium with excess iron were isolated from the PW8 strain of Corynebacterium diphtheriae. These mutants produced as much toxin in medium containing excess iron (3 mug of Fe2+ per ml) as did the parent PW8 strain in iron-depleted medium, and they will be very useful for easy production of toxin.     

Improved culture of Corynebacterium diphtheriae for obtaining toxin-anatoxin

The work deals with the optimization of the cultivation of C. diphtheriae with a view to obtaining diphtheria toxin--toxoid on the basis of the study of the kinetics of microbial growth and toxin formation. The combined cultivation process consisting of 3 cycles has been experimentally developed and realized under industrial conditions. The use of this cultivation method has made it possible to obtain more balanced cultures and to standardize the biological properties of the biomass and toxin thus obtained. The characteristic features of the toxoid preparations obtained on the basis of this method are a high degree of purification, good immunogenic properties and constant fractional composition; their degree of homogeneity approximates the molecular homogeneous state.     

Park-Williams Number 8 Strain of Corynebacterium diphtheriae

Five clones of the Park-Williams number 8 strain of Corynebacterium diphtheriae, previously maintained in separate laboratories, were examined for their colonial and biochemical properties, for the restriction and modification system which operates to obscure their lysogeny, and for their capacity to produce large amounts of toxin under ordinary laboratory conditions. The phenotypes of their phage, P, produced in strain 603 and C7 (P.603 and P.C7) differ both as to stability to storage in the cold and to inactivation by antiphage serum. Evidence for a high degree of stability in the integration of P prophage in the PW8 genome is presented.     

Accumulation of biomass and mineral elements with calendar time by corn: application of the expanded growth model

The expanded growth model is developed to describe accumulation of plant biomass (Mg ha(-1)) and mineral elements (kg ha(-1)) in with calendar time (wk). Accumulation of plant biomass with calendar time occurs as a result of photosynthesis for green land-based plants. A corresponding accumulation of mineral elements such as nitrogen, phosphorus, and potassium occurs from the soil through plant roots. In this analysis, the expanded growth model is tested against high quality, published data on corn (Zea mays L.) growth. Data from a field study in South Carolina was used to evaluate the application of the model, where the planting time of April 2 in the field study maximized the capture of solar energy for biomass production. The growth model predicts a simple linear relationship between biomass yield and the growth quantifier, which is confirmed with the data. The growth quantifier incorporates the unit processes of distribution of solar energy which drives biomass accumulation by photosynthesis, partitioning of biomass between light-gathering and structural components of the plants, and an aging function. A hyperbolic relationship between plant nutrient uptake and biomass yield is assumed, and is confirmed for the mineral elements nitrogen (N), phosphorus (P), and potassium (K). It is concluded that the rate limiting process in the system is biomass accumulation by photosynthesis and that nutrient accumulation occurs in virtual equilibrium with biomass accumulation.     

Ecological responses to nutrients in streams and rivers of the Colorado mountains and foothills

1. Abundance and composition of periphyton and benthic macroinvertebrates were treated as potential nutrient response variables for 74 streams in montane Colorado. The streams ranged from unenriched to mildly enriched with nutrients (N, P). 2. The study showed no meaningful relationship between periphyton biomass accumulation and concentrations of total or dissolved forms of nitrogen or phosphorus. Nutrient concentrations were also unrelated to periphyton and macroinvertebrate richness, diversity and community composition. Macroinvertebrate communities did, however, show a strong positive relationship to periphyton abundance. 3. A positive response of periphyton biomass to increasing nutrient concentrations has been well documented over large ranges of nutrient concentrations. Our study suggests that the nutrient response is suppressed by other controlling factors on the lower limb of the nutrient response curve (i.e. at low nutrient concentrations); a quantitatively significant response occurs only in excess of a threshold beyond which nutrients become dominant over other controlling factors. This interpretation of the results is consistent with published meta‐analyses showing lack of nutrient response for a high proportion of experimentally enriched periphyton communities, and division of responses between N and P for communities that do show growth in response to enrichment. 4. Grazing probably is not the key controlling variable for periphyton in Colorado mountain streams, given that the highest chlorophyll concentrations are associated with the highest abundances of macroinvertebrates. Modelling indicates that the initial amount of periphyton biomass at the start of the growing season, in conjunction with elevation‐related length of the growing season and water temperature, explains most of the variation in periphyton accumulation among these streams, but there is a yet unexplained suppression of periphyton growth rates across all elevations.     

Level of redox potential as a possible contributing influence in the pathogenicity of oral anaerobes

Dental plaque anaerobes may be associated with the etiology of periodontal disease. This has created an interest in the potential pathogenicity of oral anaerobes. We compared the metabolic activity of anaerobic corynebacteria (C. parvum, C. anaerobium) and corresponding aerobic species (C. diphtheriae, C. xerosis). The anaerobes exhibited lower levels of growth rate, m-RNA half-life and ribosomal efficiency but much higher levels of RNA synthesis, ranging from 5 to 10 fold over the aerobes. We further examined these anaerobes, plusActinomyces naeslundi N16 (isolated from the anaerobic region of periodontally-diseased tissues), for the influence of redox potential on RNA level and antigenic function. Notable increases in RNA were found at specific Eh levels; the extent and direction of the changes varied with the different organisms. This environmental feature appeared to effect corresponding changes in agglutinability and PCA reactivity with antisera against the anaerobes cultured at different redox potentials. For example, while antisera against certain organisms (C. parvum, A. naeslundi) cultured under the most reduced conditions showed an intense PCA reaction, other antisera against the same organism cultured under less reduced conditions were non-reactive. Hence, alterations in redox potential may lead to altered metabolism and to altered antigenicity. Our results imply such a microbial response to environmental stress.     

梯棱羊肚菌外源营养作用的影响因素

外源营养袋的应用是国内羊肚菌大田栽培成功的关键技术之一,但其作用机理和影响因素一直没有得到充分的解析。本研究首先于室内建立一个外源营养模型,确认模型中外源营养模块可以向外输出营养,且被梯棱羊肚菌菌丝利用。通过模型实验发现,外源营养添加到贫瘠培养基时,菌体生物量的增加显著高于营养丰富的培养基;在梯棱羊肚菌生长的不同阶段添加外源营养,菌核形成位置不同,并影响生物量的增加,在菌核起始阶段添加,主培养基的生物量增加最多;外源营养的添加位置、块数等因素在本模型中没有检测到对生物量的影响。外源营养使用聚丙烯袋包裹和不包裹比较发现,包裹组的主培养基内生物量增速和总量低于无包裹组,而外源营养块内趋势相反,但最终两组之间外源营养块与主培养基内生物量总和没有显著差异。使用滤纸和铝箔包裹外源营养时,对生物量的影响和聚丙烯袋材质没有显著差别。外源营养碳氮比20:1时,最有利于主培养基生物量的积累。本研究建立的外源营养研究模型得到的结论与大田栽培有较好的一致性,通过模型发现了实际栽培中不容易观察到的现象,有助于对外源营养袋作用机理进行深入研究。     

不同种植方式对花生土壤微生物生物量及活性的影响

在大田条件下,采用随机区组设计研究了春播覆膜（CBFM）、春播露地（CBLD）、麦田套种（MT）、麦田套种露地对照（MTLD）、夏播覆膜（XBFM）和夏播露地（XBLD）6种花生种植方式对土壤微生物生物量碳、活跃微生物生物量和土壤呼吸的影响.结果表明： 花生生育期和种植方式均显著影响土壤微生物生物量及活性.从始花期开始,随着生育进程的推进,土壤微生物生物量碳、活跃微生物生物量和呼吸速率逐渐升高,到结荚期达到最大值,随后下降.露地栽培花生提高了土壤微生物生物量碳和土壤呼吸速率,但是降低了活跃微生物生物量,对土壤养分的转化和吸收不利;覆膜花生提高了活跃微生物生物量,促进土壤养分的分解和有效化;麦田套种花生比同期播种的露地对照花生提高了土壤微生物生物量碳、活跃微生物生物量和土壤呼吸速率,固结养分较多,不利于花生生长.     

Dried nutrient media for the cultivation of pneumococcus and meningococcus

Dried synthetic nutrient medium for the cultivation of meningococci and the accumulation of their biomass has been developed. The kinetics of the culture growth, changes in pH and in the content of dissolved oxygen in the medium during prolonged controlled processes of the cultivation of meningococci in a bioreactor with the use of this medium have been studied. The stable physico-chemical properties and composition of the polysaccharide-protein complex isolated from the biomass of meningococci grown in the above-mentioned medium have made it possible to use it for the preparation of the samples of group B meningococcal vaccine. In addition, dried semi-synthetic nutrient medium for the accumulation of pneumococci without the necessity of introducing blood or serum into the medium has been developed. As regards its biological properties, this newly developed medium make it not inferior to meat media, containing blood or serum, and ensures good yield of biomass.     

Rosmarinic acid production by Lavandula vera MM cell-suspension culture

The time courses of growth and rosmarinic acid production by Lavandula vera MM cell suspension were investigated. The uptake of the main nutrients (sucrose, nitrogen, phosphorus, K, Ca, Mg) was followed during cultivation and the data on the physiology of the L. vera MM cell culture are presented. It was established that the cell culture synthesizes rosmarinic acid during the linear phase of growth for a relatively short period (between the 4th and 8th days of cultivation). The influence of sucrose concentration in the nutrient medium on cell growth and accumulation of rosmarinic acid by L. vera MM cell culture was investigated. The results showed that 7% sucrose in the nutrient medium ensured a steady growth of the cell suspension and increased the yield of rosmarinic acid (29.2 g/l dry biomass and 507.5 mg/l rosmarinic acid compared to 13.0 g/l dry biomass and 68.6 mg/l rosmarinic acid for the control cultivation with 3% sucrose). Received: 17 September 1996 / Received revision: 31 January 1997 / Accepted: 1 February 1997     

Restriction endonuclease map of corynebacteriophage omega ctox+ isolated from the Park-Williams no. 8 strain of Corynebacterium diphtheriae.

The toxigenic corynebacteriophage omega tox+ was isolated from the hypertoxigenic Park-Williams no. 8 (PW8) strain of Corynebacterium diphtheriae and compared with the toxigenic corynebacteriophage beta tox+. The physical size and host range of both phages were found to be identical. An endonuclease restriction map of omega tox+ was constructed, and the locations of the cohesive ends (cos), phage attachment site (attP), and the diphtheria tox operon were identified. The genome of omega tox+ was found to differ from that of beta tox+ in three regions. In addition, omega tox+ was shown to be integrated into two nontandem corynebacterial phage attachment sites (attB1, attB2) in the PW8 chromosome. The differences in the restriction endonuclease digestion maps of omega tox+ and beta tox+ and the contribution of double lysogeny are discussed in relation to the hypertoxigenicity of the PW8 strain.     

Kinetics of the processes of Streptococcus pneumoniae batch cultivation in relation to the physiological state of the inoculum

The present investigation, carried out with the use of S. pneumoniae as a model, has shown that the kinetics of cultivation processes depend on the preparation of the seed culture. The use of the seed culture, taken at the end of the exponential phase of growth, leads to high initial and maximum specific growth rates and a shorter lag phase, high productivity of the process and the economic coefficient of the yield of the biomass. If pH and pO2 are maintained at a set level, the most operative parameter of the process is the redox potential. A new informative characteristic of the cultivation process (T) is proposed. This characteristic permits the comparison of growth processes and indicates the time in which the fluctuations of Gibbs's free energy per 1000 million cells decrease to a definite level.     

Cross‐Species Alleviation of Biotic and Abiotic Stresses by the Endophyte Pseudomonas aeruginosa PW09

A wheat endophytic bacterium (Pseudomonas aeruginosa PW09) was evaluated for its ability to trigger an induced systemic resistance response in cucumber against biotic and abiotic stresses. PW09 was applied to cucumber seeds, and the seedlings were subjected to Sclerotium rolfsii infection and NaCl (150 mm ). The role of PW09 was evaluated in alleviating the stresses by assessing plant mortality due to S. rolfsii infection and biomass accumulation under NaCl stress as well as at the physiological level through phenylpropanoid metabolism, antioxidant activities and proline accumulation. The endophyte reduced seedling mortality by 60% and increased biomass accumulation significantly under S. rolfsii (7%) and NaCl (18%) stresses, respectively, compared with endophyte‐untreated seedlings. Application of PW09 also induced higher accumulation of proline (1.3‐ and 1.4‐fold) and total phenolics (1.2‐ and 1.1‐fold) and activities of polyphenol oxidase (4.3‐ and 1.5‐fold), phenylalanine ammonia lyase (1.29‐ and 1.27‐fold) and superoxide dismutase (2.5‐ and 1.39‐fold) under S. rolfsii and NaCl stresses, indicating the ability of the wheat endophyte PW09 in alleviating both biotic and abiotic stresses in cucumber.     

The use of polymerase chain reaction in the diagnosis of diphtheria infection

624 Corynebacterium diphtheriae strains, newly isolated from patients and carriers, were studied with the use of the methods of gel immunodiffusion (Elek's test) and polymerase chain reaction (PCR). In the evaluation of 388 C. diptheriae strains, found to be toxigenic in PCR, the results of Elek's test coincided with those of PCR on 98% of cases. In 38 out of 143 strains (26.5%), nontoxigenic according to the results of Elek's test, the presence of the A-fragment of the tox-gene was established. Subculturing in nutrient media made it possible to determine the presence of toxin in 19 out of 38 of these strains; the remaining strains, isolated mainly from carriers, were found to have the "silent" gene. The advantage of using PCR for the detection of toxigenic and nontoxigenic C. diphtheriae strains of different origin was shown.     

Progress in physicochemical parameters of microalgae cultivation for biofuel production

Microalgae have been exploited for biofuel generation in the current era due to its enormous energy content, fast cellular growth rate, inexpensive culture approaches, accumulation of inorganic compounds, and CO₂ sequestration. Currently, research is ongoing towards the advancement of the microalgae cultivation parameters to enhance the biomass yield. The main objective of this study was to delineate the progress of physicochemical parameters for microalgae cultivation such as gaseous transfer, mixing, light demand, temperature, pH, nutrients and the culture period. This review demonstrates the latest research trends on mass transfer coefficient of different microalgae culturing reactors, gas velocity optimization, light intensity, retention time, and radiance effects on microalgae cellular growth, temperature impact on chlorophyll production, and nutrient dosage ratios for cellulosic metabolism to avoid nutrient deprivation. Besides that, cultivation approaches for microalgae associated with mathematical modeling for different parameters, mechanisms of microalgal growth rate and doubling time have been elaborately described. Along with that, this review also documents potential lipid-carbohydrate-protein enriched microalgae candidates for biofuel, biomass productivity, and different cultivation conditions including open-pond cultivation, closed-loop cultivation, and photobioreactors. Various photobioreactor types, the microalgae strain, productivity, advantages, and limitations were tabulated. In line with microalgae cultivation, this study also outlines in detail numerous biofuels from microalgae.