[en] The research of gamma irradiated sawdust, which were added H2SO4 and NaOH solutions on fermentation process for ethanol production was investigated. Irradiation doses used were : 0 and 200 kGy, while H2SO4 and NaOH solutions had concentrations of 0,1 and 2% (v/v) and (b/v), with a ratio of sawdust weight and solution volume = 1:3. Fine powder of sawdust with a mesh of 60, was hydrolysed by enzyme (cellulase), S.cerevisiae was a yeast used for fermentation process and fermentation time was 4 hours. From the experimental results showed that irradiation doses up to 200 kGy, could increase the ethanol concentration from sawdust fermentation signivicantly (P=<0.01),(P=<0.05). The edition of acid (H2SO4) and interaction of acid and irradiation did not influence the ethanol concentration as a yield of fermentation. The effect of alcaline (NaOH) was not also significant for increasing ethanol concentration but interaction of that treatment with irradiation could increase significantly (P=<0.05>. Irradiation treatment, addition of the solutions and its interaction could not influence the total carbohydrate before and after fermentation. (author). 9 refs, 2 figs, 6 tabs

[en] This experiment was carried out to know the ethanol and total carbohydrate concentrations in fermented rice straw which was irradiated with gamma ray 60-Co from latex irradiator with the doses of 0 and 200 kGy. Rice straw was mixed with H2SO4 NaOH 0,1 and 2% (v/v), (w/v) and with CH3COOH 0, 1, 3, and 5% (v/v) in the ratio 1:4 (w/v). The rice straw was crushed to be powder 6 mesh. Cellulase was added for saccharification. The yeast strain used for fermentation was S.Cerevisiae and the incubation time was 40 hours, at room temperature (28+/-2 Celsius centigrade). Results showed that gamma irradiation with dose of 200 kGy increased the ethanol and total carbohydrate productions (P=<0.01). Additions of H2SO4, NaOH also had significant effect to enchance the ethanol production (P=<0.05), (P=<0.01) but this effect was not significant on the total carbohydrate. Treatment with adding CH3COOH on rice straw had no significant effect either on ethanol and total carbohydrate of rice straw.The effect of interaction between irradiation and addition of solutions mentioned above had no significant effects, but the ethanol production had a tendency to increase with those combination treatments. (authors). 6 refs, 3 figs, 6 tabs

[en] The application of the radiopasteurization method for alcoholic fermentation of molases media have been studied which compared to heat pasteurization. The molases samples were obtained from sugar industry in Cirebon, Yogyakarta, and Lawang, used as a samples for gamma irradiation, doses of 3 kGy, 6 kGy and heat pasteurization 80 Celcius centigrade for 30 minutes, which compared to untreated molases. Innculum yeast was S. Cerevisiae K 1.5 which was resulted by irradiation mutation. The results showed that gamma irradiation dose of 3 kGy have pasteurization effect better than 6 kGy and heat pasteurization 80 Celcius centigrade, 30 minutes. Total cells count of microflora per gram samples (% survivors) on molasses media which has been heat pasteurized, decreased to be 70%, 10% for irradiated molasses 3 kGy; and 1% for molasses irradiated 6 kGy, but it did not have significant effect on the growth capacity of S. cerevisiae K 1.5 on that molasses media. Microflora isolated from molasses samples obtained from Cirebon, Yogyakarta, and Lawang, generally from Bacillus subtilis, Lactobacillus sp., Corynebacterium sp., and Rhizopus oligosporus, although was detected but not grows well on molasses media. The growth of S. cerevisiae K 1.5 on fermentation media suplemented with trace elements nitrogen and phosphor resulted difference on fermentation rate i.e.: in irradiated molasses 3 kGy and 6 kGy showed a higher rate, which compared to heat pasteurization and controle. In the environment condition study on molasses media shows the yeast S. cerevisiae K 1.5 have optimal growth at the pH 5.5, specific growth rate 0.3-0.5 per hour, the saturation constant 0.5 - 0.60 g/l, temperature 30 +/- 2 Celcius centigrade with sugar : nitrogen : phosphor ratio = 100 : 5 : 1. The nitrogen and phosphor sources are ammonium sulphate and sodium hidrogen phosphate respectively. (author). 6 refs, 2 figs, 2 tabs

[en] An experiment to study the effect of irradiated rice husk as a substrate on cellulase production of free and immobilized cells of S. cellulophium was carried out. Radiation pretreatment of rice husk was done using electron beam accelerator (Dynamitron IEA 3000-25,2), with doses of 0, 0.2, 0.4, 0.6, 0.8, and 1.0 MGy. The substrate used in cellulase production of free and immobilized cells were cellulose powder as a standard, and 1.0 MGy irradiated rice husk. Concentrations of cellulose powder for free and immobilized cells were 1, 2, 3, 5, and 8% (w/v). Irradiated rice husk concentrations for free cells were 3, 6, 9, 15, and 24% (w/v), whereas for immobilized cells were 3, 6, and 9% (w/v). Results showed that glucose concentration in 1.0 MGy irradiated rice husk was the highest of all irradiated and unirradiated rice husks. The GPA (glucose production activity) values used of free immobilized cells of S. cellulophium in medium containing 1.0 MGy irradiated rice husk were about 50% lower than in cellulose powder medium. Cellulase solution resulted by immobilized cells, either in cellulose powder or in irradiated rice husk media, were clear and did not contain mycelium. (authors). 7 refs, 7 figs

[en] An experiment has been done with several irradiation methods to determine the sensitivity of bacteria against gamma rays. For this purpose the bacteria were irradiated with ⁶⁰Co gamma radiation with doses of 0, 0.1, 0.2 and 0.3 kGy from a multipurpose panoramic batch irradiator (PANBIT), and then grown on the surface of TGY agar. The results indicated that irradiation with oxygen but without ice gave the best lethal effect. Irradiation showed a significant effect on the ability of bacteria to multiply, and the sensitivity of the bacteria depended on its respective generation time. (author)

[en] An experiment has been conducted to find vegetative forms of certain bacteria in Indonesia which are resistant to irradiation, the resistance of which will be compared to that of known radioresistant bacteria micrococcus radiodurans. To inactivate the vegetative forms of resistant bacteria to irradiation high doses are needed, while for storage purposes lower doses change the physical and chemical properties of the stored commodity are preferred. For this purpose the bacteria were irradiated in aerobic condition with gamma radiation doses of 0.1, 0.2 and 0.3 kGy, or treated with antibiotics e.g. tetracycline HCl or chloramphenicol with concentrations of 0.1, 0.2 and 0.3 μg/ml respectively. The results indicated that doses of 0.2 kGy and 0.1 μg/ml reduced the ability of the bacteria for multiplication. (author)

[en] A study to examine the influence of gamma irradiation (Co⁶⁰) on the production of alcohol from cassava by two yeast cultures, S. cerevisiae and a thermotolerant K. marxianus was carried out. Irradiation doses used were 0; 0.1; 0.3; 0.5 and 7 kGy. Two enzymes thermamyl and amyloglucosidase were used for liquifaction and saccharification, respectively. A part of the cassava substrate was enriched with NH₄H₂PO₄ as nitrogen source. Irradiated yeast suspension (⁺_-10⁸ cells/ml) was inoculated to the medium to a final concentration of 5% (v/v). Incubation period was 3 days at a temperature of 30^oC for S. cerevisiae and 37^oC for K. marxianus. Results showed that gamma irradiation had a significant effect on the number of both yeast colonies. It decreased the number of yeast colonies, but not the content of ethanol produced by its fermentation. The yeast still viable after irradiation probably had an increased activity. Adding nitrogen to S. cerevisiae caused a decrease in the content of ethanol, but no significant effect was found on the number of colonies of both yeasts as affected by added nitrogen. (author). 10 refs