Sequential hydrolysis of waste newspaper and bioethanol production from the hydrolysate.

A practical process was developed for production of a high quality hydrolysate of waste newspaper that ensured its complete fermentability to bioethanol. After pretreatment with 0.1N NaOH for 12h and sequential acid and enzyme hydrolysis, 10.1g/L of glucose (50.5%), 1.38 g/L of mannose (6.9%) and 0.28 g/L of galactose (1.4%), a total of 11.76 g/L of fermentable sugars was obtained, which accounts for 88.7% of saccharification efficiency. The Saccharomyces cerevisiae BCRC20271 showed excellent co-fermentability of glucose, mannose and galactose in hydrolysate of waste newspaper. After cultivation of the hydrolysate at 24°C in static culture for 48 h, the final ethanol concentration of 5.72 g/L (96% conversion efficiency) was produced. Overall, 1000 kg of waste newspaper will produce 286 kg (362 L) of ethanol by the process developed, which reveals that waste newspaper has higher potential than many other lignocellulosic and seaweed feedstocks for bioethanol production.

Sequential acid and enzymatic hydrolysis in situ and bioethanol production from Gracilaria biomass.

Gracilaria sp., a red alga, was used as a feedstock for the production of bioethanol. Saccharification of Gracilaria sp. by sequential acid and enzyme hydrolysis in situ produced a high quality hydrolysate that ensured its fermentability to produce ethanol. The optimal saccharification process resulted in total 11.85g/L (59.26%) of glucose and galactose, Saccharomyces cerevisiae Wu-Y2 showed a good performance on co-fermentability of glucose and galactose released in the hydrolysate from Gracilaria sp. The final ethanol concentrations of 4.72g/L (0.48g/g sugar consumed; 94% conversion efficiency) and the ethanol productivity 4.93g/L/d were achieved. 1g of dry Gracilaria can be converted to 0.236g (23.6%) of bioethanol via the processes developed. Efficient alcohol production by immobilized S. cerevisiae Wu-Y2 in batch and repeated batch fermentation was also demonstrated. The findings of this study revealed that Gracilaria sp. can be a potential feedstock in biorefinery for ethanol production.

Cultivation of medicinal caterpillar fungus, Cordyceps militaris (Ascomycetes), and production of cordycepin using the spent medium from levan fermentation.

A process of tandem cultivation for the production of green and invaluable bioproducts (levan and Cordycepes militaris) useful for medical applications has been successfully developed. The process involves first cultivating Bacillus subtilis strain natto in sucrose medium to produce levan, followed by the subsequent cultivation of C. militaris in liquid- and solid-state cultures using the spent medium from levan fermentation as substrates. The factors affecting the cell growth and production of metabolites of C. militaris were investigated, and the various metabolites produced in the culture filtrate, mycelia, and fruiting body were analyzed. In addition, cordycepin was prepared from the solid waste medium of C. militaris. This is an excellent example in the development of cost effective biorefineries that maximize useful product formation from the available biomass. The preparation of cordycepin from solid waste medium of C. militaris using a method with high extraction efficiency and minimum solvent usage is also environmentally friendly.

Optimization of the production and characterization of milk clotting enzymes by Bacillus subtilis natto.

Suitable medium for production of milk clotting enzyme (MCE) by Bacillus subtilis (natto) Takahashi in submerged liquid-state fermentation was screened, the nutrient factors affecting MCE production was optimized by response surface methodology. The MCE production by B. subtilis (natto) Takahashi was increased significantly by 428% in the optimal medium developed. The MCE was filtered and concentrated by ultrafiltration. The retentate after tandem filtration carried out with the combined membranes of MWCO 50kDa and 5 kDa showed two major bands between 25kDa and 30kDa on SDS-PAGE, and the MCA and MCA/PA improved significantly in comparison with those in the initial broth. The crude enzyme thus obtained showed MCA and MCA/PA ratio of 48,000 SU/g and 6,400, which are commensurate with those (MCA 26,667 SU/g and MCA/PA 6,667) of the commercial rennet. It had optimal pH and temperature at pH 6 and 60°C, and showed excellent pH and thermal stability.

Sequential production of two biopolymers-levan and poly-ε-lysine by microbial fermentation.

Sequential fermentation for the production of two invaluable biopolymers, levan and poly-ε-lysine (ε-PL), has been successfully developed. It involves fermentation of Bacillus subtilis (natto) Takahashi in sucrose medium to produce levan, separation of levan product from small remaining sugar molecules by ultrafiltration and fermentation of the remnant from levan production by Streptomyces albulus to produce ε-PL. In the process, 50-60 g/L of levan was produced (100% recovery after precipitation by ethanol). The remnant from levan production with glucose adjusted to 30 g/L and with combined use of yeast extract (10 g/L), (NH(4))(2)SO(4) (2g/L) and basal salts was proven to be suitable for ε-PL production. 4.37 g/L of ε-PL accumulation (85% recovery after purification) was reached in 72 h using two-stage fermentation with control of pH. The process of using remnant (waste) from levan fermentation for the second biopolymer (ε-PL) production is unprecedented and the products obtained are environmental-friendly.

Study of mycelial growth and bioactive polysaccharide production in batch and fed-batch culture of Grifola frondosa.

The fermentation of Grifola frondosa was investigated in the shake flasks and a 5-L jar fermenter in batch and fed-batch modes. In the shake-flask experiments, the preferable mycelial growth and exopolysaccharide (EPS) production was observed at relatively low pH; maltose and glucose were preferred carbon sources for high mycelial production. The EPS was doubled after 13 d of cultivation when glucose was increased from 2% to 4%. Yeast extract (YE) (0.4%) in combination with corn steep powder (CSP) (0.6%) and YE (0.8%) in combination with CSP (1.2%) were preferred nitrogen sources for high mycelial production and EPS production, respectively. All plant oils tested significantly stimulate cell growth of G. frondosa but they failed to enhance EPS production. The EPS products usually consisted of two fractions of different molecular sizes varied by the plant oils used. The fed-batch fermentation by glucose feeding was performed when the glucose concentration in the medium was lower than 0.5% (5g/L), which greatly enhanced the accumulation of mycelial biomass and EPS; the mycelial biomass and EPS were 3.97g/L and 1.04g/L before glucose feeding, which reached 8.23g/L and 3.88g/L at 13 d of cultivation. In contrast, the mycelial biomass and EPS in the batch fermentation were 6.7g/L and 3.3g/L at 13 d of cultivation.

Microbial synthesis of poly(epsilon-lysine) and its various applications.

This review article deals with the microbial synthesis, physiochemical properties, and potential applications of poly-epsilon-lysine (epsilon-PL), which is a naturally occurring biomaterial that is water soluble, biodegradable, edible and non-toxic toward humans and the environment. The potential applications of epsilon-PL as food preservatives, emulsifying agent, dietary agent, biodegradable fibers, highly water absorbable hydrogels, drug carriers, anticancer agent enhancer, biochip coatings in the fields of food, medicine, agriculture and electronics are also discussed in this review.

selective production and characterization of levan by Bacillus subtilis (Natto) Takahashi.

To meet the industrial need of an efficient microbial method for increased levan production, Bacillus subtilis (natto) Takahashi, a commercial natto starter for preparing fermented soybeans (natto), was used to produce levan. After cultivation for 21 h, 40-50 mg of levan mL(-1) was produced in medium containing 20% (w/w) sucrose, which was approximately 50% yield on available fructose. The product consisted of two fractions with different molecular masses (1794 and 11 kDa), which were easily separated by fractionation using an ethanol gradient. The products were well characterized by GPC, 13C NMR, and 1H NMR. The various sugars and concentrations, initial pH, fermentation temperature, and agitation speed affected the levan production by B. subtilis (natto) Takahashi. Takahashi strain is the most efficient levan-producing strain among all of the B. subtilis strains tested and, as previously reported, it produced the highest yield of levan in the least time (21 h) under the common cultivation condition.

Simultaneous and selective production of levan and poly(gamma-glutamic acid) by Bacillus subtilis.

Bacillus subtilis(natto) Takahashi, used to prepare the fermented soybean product natto, was grown in a basal medium containing 5% (w/w) sucrose and 1.5% (w/w) L-glutamate and produced 58% (w/w) poly(gamma-glutamic acid) and 42% (w/w) levan simultaneously. After 21 h, 40-50 mg levan ml-1 had been produced in medium containing 20% (w/w) sucrose but without L-glutamate. In medium containing L-glutamic acid but without sucrose, mainly poly(gamma-glutamic acid) was produced.

Optimization of lipase-catalyzed synthesis of octyl hydroxyphenylpropionate by response surface methodology.

The ability of immobilized lipase Candida antarctica (Novozyme 435) to catalyze the direct esterification of hydroxyphenylpropionic acid and octanol in a solvent-free system was investigated in this study. Response surface methodology (RSM) and five-level-four-factor central composite rotatable design (CCRD) were employed to evaluate the effects of synthesis parameters, such as reaction time, temperature, enzyme amount, and pH memory, on percentage molar conversion of phenolic acid esters. Reaction time, temperature, and enzyme amount were the most important variables. On the basis of canonical analysis and ridge max analysis, the optimum synthesis conditions with 95.9% molar conversion were reaction time of 58.2 h, temperature of 52.9 degrees C, enzyme amount of 37.8% (w/w), and pH memory of pH 7.

Antifreeze activities of poly(gamma-glutamic acid) produced by Bacillus licheniformis.

Various enantiomeric isomers, metals salts and molecular sizes of poly(gamma-glutamic acid), gamma-PGA, produced by Bacillus licheniformis CCRC 12826, were prepared and their antifreeze activities were studied by differential scanning calorimetry. The antifreeze activity of gamma-PGA increased as its molecular weight decreased but was indifferent to its D/L-glutamate composition. The antifreeze activity was cation dependent decreasing in the order Mg2+ >> Ca2+ approximately Na+ >> K+ which follows that of inorganic chlorides in that high ionic charge leads to high antifreeze activity. The mechanism by which the cryoprotective effects of gamma-PGA can be explained is still yet to be determined.

Purification and characterization of two antifungal chitinases extracellularly produced by Bacillus amyloliquefaciens V656 in a shrimp and crab shell powder medium.

A Gram-positive bacterium with antagonistic activity was isolated from the soil. It has been identified as Bacillus amyloliquefaciens strain V656 on the basis of 16S ribosomal DNA analysis and standard bacteriological tests. B. amyloliquefaciens V656 produced antifungal enzymes when it was grown in a medium containing shrimp and crab shell powder (SCSP) of marine waste. The antifungal enzymes displayed chitinase activities. Two extracellular antifungal chitinases (FI and FII) were purified and characterized, and their molecular weights, isoelectric points, pH and thermal stabilities, and antifungal activities were determined. The characteristics of V656 chitinases are similar to those of the known bacterial chitinases in terms of their isoelectric points, thermal instabilities, and lack of lysozyme activity. In contrast to other known bacterial chitinases, the unique characteristics of V656 chitinases include extremely low molecular weights and nearly neutral optimum pH. Furthermore, this is the first report of the isolation of chitinases from B. amyloliquefaciens that are active against fungi.