New yeast strains for alcoholic fermentation at higher sugar concentration

Summary New yeast strains for alcoholic fermentation were isolated from samples collected from Brazilian alcohol factories at the end of the sugar cane crop season. They were selected by their capacity of fermenting concentrated sugar cane syrup as well as high sucrose concentrations in synthetic medium with a conversion efficiency of 89–92%. The strains were identified asSaccharomyces cerevisiae.     

System for Detecting Inducers of Lysogenic Escherichia coli W1709(λ) and Its Applicability as a Screen for Antineoplastic Antibodies

Studies were conducted to determine conditions of maximal sensitivity for a test system designed to detect chemical inducers of phage production in the streptomycin-dependent, lysogenic Escherichia coli strain W1709(λ). This strain was found to be induced by all antibiotics previously reported to be inducers of E. coli K-12(λ). However, the system employing W1709(λ) proved superior for screening fermentation filtrates because its growth, in contrast to that of K-12(λ), was not stimulated during the induction period by filtrate nutrients. Thus, misleading high phage counts, which accompany cell growth stimulation, were not produced by filtrates devoid of inducing activity. The inducing capability of 95 fermentation filtrates, each containing an unidentified antibiotic(s) inhibitory for one or more transplanted rodent tumors, was determined in the W1709(λ) system. A low incidence of inducers was found among inhibitors of sarcoma 180, adenocarcinoma 755, solid myeloid leukemia C1498, and adenocarcinoma of the duodenum in the hamster. However, seven of eight filtrates active against leukemia 1210 had induction capability. From a screen of actinomycete culture filtrates, 28 of the first 1,000 were identified as producers of induction activity. Thus far, of the nine cultures from this group that were subjected to examination, eight demonstrated at least presumptive evidence of antineoplastic activity.     

Strain selection criteria for Penicillium funiculosum in enzymic hydrolysis of lignocellulosics

Summary The mutants ofPenicillium funiculosum viz. N-4, BU-36 and Cu-1 producing different proportions of cellulase components have been isolated. Results of saccharification experiments using various lignocellulose substrates with culture filtrates of these mutants suggested criteria for their selection.     

Use ofClostridium acetobutylicum P262 for production of solvents from whey permeate

Summary The production of solvents from whey permeate in batch fermentation usingClostridium acetobutylicum P262 was examined. An overall reactor productivity of 0.24 g/l.h was observed, representing a marked improvement over reports using other strains of clostridia. Using a semi-synthetic medium galactose was shown to be as effective a substrate as glucose. When whey permeate was used in which the lactose was hydrolysed prior to fermentation, preferential uptake of glucose over galactose was observed, and such hydrolysis provided no advantage to the fermentation process.     

Utilization of grape must and concentrated rectified grape must to produce gluconic acid by Aspergillus niger,in batch fermentations

Summary Grape must and concentrated rectified grape must were used for the gluconic acid synthesis using Aspergillus niger batch cultures. The latter substrate was the better, with a production, at 72 h, of 67.43 g/l and a yield (calculated on converted glucose) of 0.96. Citric acid was also observed as a by-product. In order to decrease the residual fructose content, at the end of the gluconate production cycle, an experimental model of sequential fermentation A. niger — Rhizopus arrhizus was proposed for the synthesis of gluconic and fumaric acid. The use of Glucose-isomerase (EC 5.3.1.5) to convert fructose to glucose was also tested.     

Use of chemostat for selection ofStreptomyces hygroscopicus mutants altered in regulation of maltose utilization

Summary Streptomyces hygroscopicus mutants showing altered fermentation kinetics were isolated using a selection procedure in a chemostat. Several mutants were obtained which differed in their capacity to produce the macrolide antibiotic turimycin.     

Elicitation of anthocyanin production in cell cultures of carrot (Daucus carota L) by using elicitors and abiotic stress

Summary A cell line of carrot (Daucus carota L) which produces anthocyanin was subjected to various elicitors and abiotic stresses: The elicitors tested were culture filtrates (CF) and cell extracts (CE) of certain bacteria and yeasts. The abiotic stresses were salts of certain metal ions. The production increase obtained with cell extracts of Bacillus cereus. Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus were 49, 72, 45 and 41% respectively over the control. Maximum elicitation was obtained with elicitor derived from cell extract of the yeast Rhodotorula rubra where it enhanced anthocyanin production by two fold. The abiotic stress agents Ca, Mn, Zn, Co, Fe & V enhanced anthocyanin production. Of all the metal ions tested Ca was the most effective. The elicitation process was governed by the type and level of elicitor.     

Use of a rapid ultrafiltration technique in the determination of plasma glycerol

The use of plasma ultrafiltrates in the enzymatic analysis of glycerol has been compared with filtrates prepared by using metaphosphoric acid and heat denaturation. The results which were obtained with these three methods of deproteinization are comparable; however, the membrane ultrafiltration technique is the simplest of the procedures and yields an undiluted filtrate which is free of foreign ions.     

Top and bottom yeasts together accelerate ethanol production in molasses fermentation

Summary Alcohol producing top and bottom yeasts were employed individually and together to assess their role in enhancing the rate of ethanol production, in cane molasses fermentation, at 30°C. The combination of top yeastS.cerevisiae NCIM 3281, and bottom yeastS.uvarum NCIM 3509, improved the enthanol production rate by 32.6% in batch fermentation and 25.2% in recycling yeasts cell fermentation as compared to their mean value of individual ethanol production activity.     

Red oak wood derived inhibitors in the ethanol fermentation of xylose byPichia stipitis CBS 5776

Summary Xylose, the predominant sugar in red oak prehydrolysate, is fermented to ethanol byPichia stipitis CBS 5776. Toxic model compounds derived from red oak hemicelluloses, lignin, and extractives inhibited the fermentation. Treatment of the prehydrolysate with molecular sieve and mixed bed ion resins facilitated the ethanol fermentation giving about 10 g/l ethanol from 32 g/l initial xylose. Fermentation inhibitors derived from red oak lignin and extractives were identified.     

Ethanol fermentation of hexose and pentose wood sugars produced by hydrogen-fluoride solvolysis of aspen chips

Summary Hexose and pentose sugars, produced by hydrogen-fluoride solvolysis of aspen wood chips, were totally consumed in a coculture fermentation by Zymomonas mobilis and a mutant of Clostridium saccharolyticum. Z. mobilis converted the glucose to ethanol, while the mutant, which was improved in both ethanol production and tolerance, converted the xylose component to ethanol. A high conversion efficiency of wood sugars to ethanol was obtained, and the cells after the fermentation were successfully used for cell recycle.NRCC no. 23211     

Selection of preculture conditions for solid state fermentation of sugar beet pulp

Summary For the protein upgrading of sugar-beet pulp in solid state fermentation byTrichoderma reesei andFusarium oxysporum, serveral conditions were studied to prepare an economical preculture for large scale process. The best performance was shown by a preculture obtained in 24 h from 1.5 % molasses solution at pH 4.5–5.0 with 1.0 % milled beet pulp.     

Conversion of sugar-beet particles to ethanol by the bacteriumZymomonas mobilis in solid-state fermentation

Summary The possibility of usingZymomonas mobilis as the microorganism, in solid-state fermentation of sugar-beet particles was investigated. The major factors affecting the process were investigated and related to ethanol yield and productivity. Ethanol yield of 0.48 g/g sugar, volumetric productivity of 12 g/L h, and final ethanol concentration of 130 g/L show the good performance ofZ.mobilis in a solid-state fermentation.     

Optimization of growth conditions for the induction of tyrosine decarboxylase inStreptococcus faecalis

Summary Growth conditions were investigated for optimal tyrosine decarboxylase (EC 4.1.1.25) activity in acetone dried cells ofStreptococcus faecalis. A growth pH of 6.0 was found optimal for enzyme induction. The enzyme was also shown to be growth-associated which indicates that continuous fermentation is preferable for optimal process productivity.     

Butanol production from cellulosic substrates by sequential co-culture ofClostridium thermocellum andC.acetobutylicum

A sequential co-culture approach was investigated for the conversion of lignocellulosic substrates to fuels and chemicals. Growth ofClostridium acetobutylicum on solka floc (or a mixture of solka floc and aspenwood xylan), in co-culture withC.thermocellum, resulted in the efficient utilization of all the hydrolysis products derived from the lignocellulosic substrates. This co-culture approach resulted in a 1.7–2.6 fold increase in the total fermentation products formed. The majority of the fermentation products were acids and not solvents, however the solventogenesis step could be induced by the addition of butyric acid to the fermentation medium.     

Development of a fermentation procedure to produce a tempe-related food using common beans as substrate

Summary A basic procedure was developed to produce a tempe-like product using the mouldRhizopus oligosporus and black common beans (Phaseolus vulgaris) as substrate. The initial pH of the substrate was 5.8, and fermentation was conducted at 37°C with a relative humidity of 70% for 72 hrs. Levels of soluble solids and soluble protein increased dramatically as a result of fermentation. Some changes were as well observed in fatty acid contents of fermented samples. It was concluded that the common bean used was an acceptable substrate for preparing this product.     

Film fermentor for ethanol production by yeast immobilized on cotton cloth

Summary Saccharomyces cerevisiae cells were immobilized on cotton cloth. The resulting yeast films were placed in parallel in a rectangular fermentor which was designed for scale-up. Ethanol production from sugars in the hydrolysate of Jerusalem artichoke tubers was studied in three modes of operation: batch, circulated batch and continuous flow. Circulated batch fermentation gave the shortest time of fermentation and accordingly the highest average ethanol productivity.     

Simultaneous saccharification and fermentation by mixed cultures ofBrettanomyces clausenii andPichia spipitis R of SO2-prehydrolysed wood

Summary Using pilot scale Wenger and Stake II reactors for prehydrolysing aspen and coniferous wood chips in the presence of SO₂ catalyst, highly digestible lignocellulosic substrates were generated from which about 90% yields of hemicellulose mostly in monomeric form could be recovered. Simultaneous saccharification and fermentation (SSF) of these SO₂ feedstocks by a mixed culture ofBrettanomyces clausenii andPichia stipitis R resulted in rapid and efficient fermentation giving a final yield of 369 and 360 L ethanol/tonne of the prehydrolysed woods, respectively. BecauseB. clausenii is an excellent cellobiose fermenter, no -glucosidase was needed during SSF.     

Characterization of extracellular substrate specific glucose and xylose isomerases of Chainia

Summary Specific glucose and xylose isomerases have been identified in cell-free culture filtrates of a Chainia species. Treatment with DEAE-cellulose selectively adsorbed xylose isomerase activity while only the glucose isomerase was adsorbed on CM-cellulose. Glucose isomerase was completely inhibited by xylose at 1.3 × 10^-4 M concentration. The differential identity of the extracellular glucose and xylose isomerases, unique to Chainia, is discussed.(NCL Communication 3562)     

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.