Abstract: Sir: In the course of our biosynthetic studies on leucomycin, a 16-membered macrolide antibiotic, it was found that leucomycin As is formed by the bioconversion of leucomycin A1 and that this reaction is repressed by butyrate1). However, since butyrate is a precursor of leucomycin2), it is difficult to evaluate whether it is directly involved in the repression of enzyme synthesis. In fact, the effect of butyrate was found to depend on glucose in the medium. In the present paper, we describe the effect of glucose on the bioconversion of leucomycin Al (LM Al) into leucomycin As (LM As) which is the 3-O-acetyl derivative of leucomycin A13) Leucomycin As accumulation was predominantly extracellular in Streptomyces kitasatoensis 66-14-3, one of the major producing strains of leucomycins Al and A3. When the culture was grown in medium I containing 2 % glucose, 0.5% peptone, 0.5% meat extract and 0.5 NaCl (pH 7.0), the level of leucomycin As accumulated was reduced by the addition of butyrate\". The production of leucomycin As was also reduced in medium II, in which the glucose component of medium I is replaced by 2 % soluble starch. The composition of the leucomycin mixture remained unchanged upon addition of butyrate to medium II. When glucose was added to medium II, the production of leucomycin As was the same as in medium I, but it was reduced by the addition of butyrate. We then examined the effect of glucose on the bioconversion of leucomycin Al into leucomycin As in a resting cell system. In this resting cell system, the de novo synthesis of leucomycin is inhibited by cerulenin4), an inhibitor of ,8ketoacyl-thioester synthase. As shown in Table 1, the bioconversion did not occur when mycelia had been grown in medium II irrespective of whether glucose was present or absent from the resting cell system. On the other hand, even in the absence of glucose in the resting cell system, the bioconversion took place if the mycelia had been grown in the presence of glucose. The bioconversion was therefore dependent on glucose in the growing cell culture but not in the resting cell system. This indicates3) that glucose is acting as an inducer of enzyme synthesis, not as an activator of the enzyme.

Abstract: This invention relates to a process whereby sterols from various sources are prepared for subsequent fermentation by dissolving the sterols in an organic diluent with subsequent removal of the organic diluent producing high substrate concentrations for fermentation.

Abstract: The fundamental determinants limiting the feasibility in bioconversion of solar energy for food, feed, fertilizer, and fermentable substrates may be categorized as technical, economical and sociological. Technical determinants are related to the amount of solar energy available and the efficiency of bioconversion. The amount of solar energy is mainly determined by location on the surface of the earth whereas photosynthetic efficiency is closely related to species specific growth rates. Light availability, nutrient base, temperature, and organism size and metabolic characteristics are among the factors influencing growth rate and efficiency. Because of low efficiency and other adverse characteristics of higher plants, it appears likely that the microalgae are the only organisms which can be produced at sufficiently high and sustained photosynthetic efficiencies to make biological transformation of solar energy, for energy alone,economically feasible. There is little question that algae produced on a large-scale would now be economically feasible for human food, animal feed, and for fertilizer if competitive markets were available. However, economical, political and sociological restrictions appear to be major barriers to current widespread applications. It seems likely that as the world food and protein crisis and the inadequacies of conventional agriculture to meet this crisis become more widely recognized acceptance and growing application of algal technology will occur in the developed and developing nations of the world. This, in turn, should permit new levels of environmentally sound abundances of food in the world.

Abstract: Progress is reported in several areas of research. The following cellulosic raw materials were selected for study: wheat, barley, and rice straws, rice hulls, sorghum, corn stover, cotton gin trash, newsprint, ground wood, and masonite steam-treated Douglas fir and redwood. Samples were collected, prepared, and analyzed for hexosans, pentosans, lignin, ash, and protein. Results of acid extraction and enzymatic hydrolysis are discussed. Yields of glucose, polyglucose, xylose, and arabinose are reported. Progress in process design and economic studies, as well as pilot plant process development and design studies, is summarized. (JGB)

Abstract: Bioconversion of the antibiotic steffimycinone to the antibiotic steffimycinol. Steffimycinol is active against various microorganisms, for example, Bacillus subtilis, Mycobacterium avium and Streptococcus pyogenes. Steffimycinol is converted to 7-deoxysteffimycinol by a microaerophilic Aeromonas hydrophila fermentation. 7-Deoxysteffimycinol is active against Sarcina lutea, Bacillus cereus, and B. subtilis. Thus, these antibiotics can be used to inhibit the growth of the above microorganisms in various environments.

Abstract: Bioconversion of the antibiotic steffimycinone to the antibiotic steffimycinol. Steffimycinol is active against various microorganisms, for example, Bacillus subtilis, Mycobacterium avium and Streptococcus pyogenes. Steffimycinol is converted to 7-deoxysteffimycinol by a microaerophilic Aeromonas hydrophila fermentation. 7-Deoxysteffimycinol is active against Sarcina lutea, Bacillus cereus, and B. subtilis. Thus, there antibiotics can be used to inhibit the growth of the above microorganisms in various environments.

Abstract: Bioconversion of the antibiotic steffimycinone to the antibiotic steffimycinol. Steffimycinol is active against various microorganisms, for example, Bacillus subtilis, Mycobacterium avium and Streptococcus pyogenes. Steffimycinol is converted to 7-deoxysteffimycinol by a microaerophilic Aeromonas hydrophila fermentation. 7-Deoxysteffimycinol is active against Sarcina lutea, Bacillus cereus, and B. subtilis. Thus, these antibiotics can be used to inhibit the growth of the above microorganisms in various environments.