Cytological changes associated with alkaloid production in cultured cells of Coptis japonica and Thalictrum minus

Cell structures were compared between alkaloid-producing and non-producing cell cultures of Coptis japonica and Thalictrum minus by electron microscopic observation. In alkaloid-producing cells of C. japonica, prior to the onset of alkaloid synthesis, the vacuoles showed a greater volume than in non-producing cells. These were characterized by a number of large starch grains in the cytoplasm. Furthermore, alkaloid-producing cells contained stacks of rough endoplasmic reticulum. Comparison of different cell lines suggested that there might be a negative correlation between accumulation of alkaloids and starch. Similar cytological differences were observed with T. minus cell cultures that release berberine into the culture medium. Alkaloid producing cells were found to contain an abundance of cytoplasmic vesicles (0.5 – 1 m in diameter).     

Butane 2,3-diol production by Aeromonas hydrophila grown on starch

Summary The conversion of soluble starch to butane 2,3-diol by Aeromonas hydrophila was investigated. The diol was produced optimally at pH 6.2 to 5.0. A significantly higher yield of the diol occurred in media buffered with potassium rather than sodium phosphates. The addition of relatively low concentrations of sodium acetate ( 1g/l) to the starch-based growth medium caused substantial increases in the yield of the diol, although no obvious proportional relationship between the amount of acetate added and the enhanced yield of the diol was recorded. The addition of 5g/l of sodium acetate caused severe growth inhibition and decreased the amount of butane 2,3-diol produced.     

A model substrate for solid-state fermentation

Summary A model substrate consisting of cassava starch embedded in kappa-carrageenan was used to mimic the growth ofRhizopus oligosporus on cassava tubers. Growth on the model substrate was similar to that during solid-state fermentation of the actual cassava. However, protein production and starch utilization were slower on the model substrate.     

Diol production byAeromonas hydrophila: Comparison of different immobilization techniques

Summary Techniques for immobilizing intact cells ofAeromonas hydrophila by cross-linking, attachment to an inorganic matrix, or entrapment in a polymeric gel are compared. Cells immobilized on a titanium (IV) hydroxide matrix were suitable for producing butane 2,3-diol from starch, whereas cells entrapped in polyacrylamide were a better catalyst for producing the diol from glucose.     

A morphometric analysis of cellular differentiation in root caps ofCucurbita peop

In order to quantify the ultrastructural changes that occur during cellular differentiation in an “open” type of root cap, we have performed a morphometric analysis of the ultrastructures of calyptrogen, columella, and peripheral cells of the root cap ofCucurbita pepo. The relative volumes of nuclei, nucleoli, and mitochondria decrease as cells move (i.e., differentiate) through the root cap. Before cells are sloughed from the cap, the relative volume of the vacuole increases by 250%. The relative volumes of plastids and plastid starch increase as calyptrogen cells differentiate into columella cells, but decrease as columella cells differentiate into peripheral cells. Dictyosomal volumes increase only as columella cells differentiate into peripheral cells. These results indicate that the five cell types comprising the root cap ofC.pepo are each characterized by a unique structure, and that the ultrastructural changes associated with cellular differentiation in root caps are organelle specific. These results are discussed relative to the functions of the various cell types of the root cap.     

Formation of a raw starch-hydrolyzing alpha-amylase by Clostridium 2021: Effect of carbon sources

Summary Clostridium 2021 was found to produce -amylase effective at hydrolyzing raw starch. Of the carbohydrates examined, starch at 3 % concentration was found to be the best carbon source for enzyme production. The products of -amylase action on starch were: maltose. glucose and higher dextrins.     

Cytological changes associated with induction of anthraquinone synthesis in photoautotrophic cell suspension cultures of Morinda lucida

Differences in subcellular structures between anthraquinone-producing and non-producing cells were investigated using photoautotrophic and photoheterotrophic cell suspension cultures of Morinda lucida. Irregular or distorted plastids containing starch grains were observed in the anthraquinone-producing cells, together with a highly elongated rough endoplasmic reticulum. The possible participation of plastids and rough endoplasmic reticulum in the anthraquinone biosynthesis is discussed.     

Cellulose acetate entrapment of Escherichia coli on cotton cloth for aspartate production

Summary Aspartase containingEscherichia coli cells were entrapped in cellulose acetate aggregated on cotton cloth. The enzyme activity of the cloth was stabilized by treatment with polyethylenimine and alkaline glutaraldehyde in the presence of 0.1 M sodium dithionite. A column packed with the cloth segments catalyzed 100% conversion of 1 M ammonium fumarate to aspartic acid at a space velocity of 7/h. When the same cloth segments were stirred at 100 rpm in the substrate solution, the productivity of the cloth increased 2.5 times.     

Growth of Candida utilis on enzymatically hydrolysed cassava

Summary Enzymatically hydrolysed cassava starch was used for C. utilis cultivation. Highly efficient starch hydrolysis was achieved with a 92% DE syrup obtained after 15–20h. Cyanide content fell during cassava processing to very low levels in the hydrolysate. Comparison of biomass yields and protein of C. utilis using molasses and cassava hydrolysate as substrates demonstrates the potential of the latter for yeast production.     

Regulation of alpha-amylase production inBacillus licheniformis M27 by enzyme end-products in submerged fermentation and its overcoming in solid state fermentation system

Summary Alpha-amylase production byBacillus licheniformis M27 in submerged fermentation was reduced from 480 to 30 units/ml when soluble starch concentration in medium was increased from 0.2 to 1.0%. In contrast, the enzyme production increased by 29 times even with 42 fold increase in the concentration of soluble starch and other starchy substrates in solid state fermentation system. The data establish regulation of the enzyme formation by enzyme end-product in submerged fermentation and ability of solid state fermentation to minimize it significantly. These features were not known earlier.     

Fermentation of starch to ethanol by a complementary mixture of an amylolytic yeast andSaccharomyces cerevisiae

Summary Synergistic coculture of an amylolytic yeast (Saccharomycopsis fibuligera) andS. cerevisiae, a non-amylolytic yeast, fermented unhydrolyzed starch to ethanol with conversion efficiencies over 90% of the theoretical maximum. Fermentation was optimal between pH 5.0 to 6.0. Using a starch concentration of 10% (w/v) and a 5% (v/v) inoculum ofS. fibuligera, increasingS. cerevisiae inoculum from 4% to 12% (w/v) resulted in 35–40% (w/v) increase in ethanol yields. Anaerobic or limited aerobic incubation almost doubled ethanol yields.     

Thermophilic methanogenesis from sugar beet pulp by a defined mixed bacterial culture

Summary Thermophilic degradation of sugar beet pulp was studied in batch cultures at 55°C by different associations of bacteria, includingClostridium thermocellum,Methanobacterium sp. andMethanosarcina MP.C. thermocellum produced acetate, succinate, methanol, ethanol, H₂ and CO₂. The coculture ofC. thermocellum andMethanobacterium sp. produced trace amounts of ethanol and succinate; acetate concentration was about three times higher than in theC. thermocellum monoculture. The association of this coculture withMethanosarcina MP produced 5.5 mmol CH₄/g dry weight sugar beet pulp.     

Production of ℓ-malic acid by Paecilomyces varioti

Summary Preliminary data for production of -malic acid from calcium acetate byPaecilomyces varioti is presented. Shake flask cultures with free cells and with cells immobilised in calcium alginate beads gave comparable results, acid concentrations of approximately 8 g/l being produced after 5 days from a medium containing 4% w/w of calcium acetate. A packed bed reactor, operated as an extended batch with product recycle, produced maximum acid concentrations of 32.6 g/l, equivalent to 73% of the maximum theoretical yield, after 3 days. Evidence obtained indicated that spores were more active than mycelia in the production of malic acid.     

Ethanol production from cassava and sago starch using Zymomonas mobilis

Summary Cassava and sago starch were evaluated for their feasibilities as substrates for ethanol production using Zymomonas mobilis ZM4 strain. Before fermentation, the starch materials were pretreated employing two commercial enzymes, Termamyl (thermostable -amylase) and AMG (amyloglucosidase). Using 2 l/g of Termamyl and 4 l/g of AMG, effective conversion of both cassava and sago starch into glucose was found with substrate concentration up to 30%(w/v) dry substances. Fermentation study performed using these starch hydrolysates as substrates resulted in ethanol yield at an average of 0.48g/g by Z. Mobilis ZM4.     

The effect of temperature and light intensity on hydrogen gas production by different Rhodopseudomonas capsulata strains

Summary Six strains of Rhodopseudomonas capsulata were tested for their ability for anaerobic light-dependent hydrogen gas production from acetate in different incubation temperatures and light intensities.Certain strains show a higher efficiency of acetate conversion to H₂ at higher temperatures and higher light intensities, others on the other hand are insensitive or even show the opposite effect.     

Sodium phosphate enhancement of starch hydrolysis by a diastatic strain of Saccharomyces cerevisiae

Summary Low concentrations of inorganic phosphate stimulate by up to 2-fold aerobic growth ofS. cerevisiae N.C.Y.C. 625 in starch medium. No such stimulation of growth is seen in a glucose medium. Enhanced growth on starch appears to result from increased secretion of glucoamylase (1,4--D-glucan glucohydrolase, EC 3.2.1.3) into the culture medium.     

β-Amylolytic activities ofEmericella nidulans (eidam) vuill

Summary Screening of fungal isolates led to selection of a strain ofEmericella nidulans 45 producing exocellular -amylase in a starch medium. Studies of dialysed enzyme and the formulation of the medium for the enzyme production are presented.     

A high molecular weight plasmid ofZymomonas mobilis harbours genes for HgCl2 resistance

Summary Plasmids fromZ. mobilis could be stably maintained inE. coli HB101 in which the expression of various drug resistance markers could be monitored. A large molecular weight plasmid (5.2 kbp) ofZ. mobilis was found to harbour the genes for mercuric chloride degradation and to confer uponE. coli, resistance to a higher mercuric chloride concentration as compared toZ. mobilis. The introduction of this plamsid madeE. coli sensitive to concentrations of cadmium acetate which were originally non-inhibitory to it.     

Direct and quantitative conversion of starch to ethanol by the yeast Schwanniomyces alluvius

Summary The yeast Schwanniomyces alluvius ferments soluble starch to ethanol at a conversion efficiency of greater than 95%. Only trace amounts of side products are detectable.NRCC publication no. 20435.     

Acetate and Bicarbonate Assimilation and Metabolite Formation in Chlamydomonas reinhardtii: A 13C-NMR Study

Cellular metabolite analyses by ¹³C-NMR showed that C. reinhardtii cells assimilate acetate at a faster rate in heterotrophy than in mixotrophy. While heterotrophic cells produced bicarbonate and CO₂ ^aq, mixotrophy cells produced bicarbonate alone as predominant metabolite. Experiments with singly ¹³C-labelled acetate (¹³CH₃-COOH or CH₃-¹³COOH) supported that both the ¹³C nuclei give rise to bicarbonate and CO₂ ^aq. The observed metabolite(s) upon further incubation led to the production of starch and triacylglycerol (TAG) in mixotrophy, whereas in heterotrophy the TAG production was minimal with substantial accumulation of glycerol and starch. Prolonged incubation up to eight days, without the addition of fresh acetate, led to an increased TAG production at the expense of bicarbonate, akin to that of nitrogen-starvation. However, such TAG production was substantially high in mixotrophy as compared to that in heterotrophy. Addition of mitochondrial un-coupler blocked the formation of bicarbonate and CO₂ ^aq in heterotrophic cells, even though acetate uptake ensued. Addition of PSII-inhibitor to mixotrophic cells resulted in partial conversion of bicarbonate into CO₂ ^aq, which were found to be in equilibrium. In an independent experiment, we have monitored assimilation of bicarbonate via photoautotrophy and found that the cells indeed produce starch and TAG at a much faster rate as compared to that in mixotrophy and heterotrophy. Further, we noticed that the accumulation of starch is relatively more as compared to TAG. Based on these observations, we suggest that acetate assimilation in C. reinhardtii does not directly lead to TAG formation but via bicarbonate/CO₂ ^aq pathways. Photoautotrophic mode is found to be the best growth condition for the production of starch and TAG and starch in C. reinhardtii.