Optimum Inoculum Size Research Articles

Gypenosides Production and Spermatogenesis Recovery Potentials of Extracts from Cell Suspension Cultures of Gynostemma pentaphyllum

Background: Gynostemma pentaphyllum (GP), also called Giao-co-lam, is a traditional Vietnamese herb, also known as the "Herb of Immortality", that grows throughout Asian countries and is used for the treatment of hematuria, edema in the pharynx and neck, tumors, and trauma.
 Methods: In this study, we investigated the effects of culture conditions on cell growth and total gypenoside accumulation in the GP suspension cells. Cells were cultured on Murashige and Skoog (MS) medium supplemented with 2.0 mg/L KIN and 0.5 mg/L IBA, and different inoculum sizes (2-4 g) for 10-24 days.
 Results: The results showed that the optimum inoculum size and shaking speed were 3 g of callus and 120 rpm, respectively. The highest cell biomass reached was 5.833 g of fresh weight, corresponding to 0.136 g of dry weight after 20 days of culture. The total gypenoside and Rb1 accumulation was the highest after 18 days of culture, with 46.498 mg/g and 0.038 mg/g dry weight, respectively. In addition, the crude extract from GP cell suspension cultures remarkably improved pathological changes in mouse testicular tissue after scrotal heat exposure. Blood testosterone levels were significantly increased in heat-exposed mice treated with the GP cell suspension culture extract.
 Conclusion: Taken together, these results suggest that GP bio-mass production by cell suspension cultures leads to the accumulation of gypenosides in large amounts, and provides the potential for the recovery of spermatogenesis following heat stress.

Isolation of an Acidophilic Cellulolytic Bacterial Strain and Its Cellulase Production Characteristics

The aim of the study was to isolate and identify a highly efficient cellulolytic bacteria strain that can be used in acidic environments, and then investigate its cellulase production characteristics for the effective utilization of agricultural waste. For this purpose, we set a series of isolation and screening steps, 21 strains were isolated from soil, and an acidophilic strain labeled as B13-2 with high cellulase production was screened using the Gram’ iodine method and cellulase activity assay; it was identified as Raoultella terrigena. Lastly, the culture conditions such as incubation time, incubation temperature, pH, carbon sources, nitrogen sources, and inoculum size were optimized via single-factor experiments, and on this basis, the cellulase production of strain B13-2 was optimized using response surface methodology with cellulase activity as the optimization goal. The results of the response surface optimization showed that the optimum incubation time is 3.1 days, the optimum temperature is 29.9 °C, the optimum pH is 4.1, and the optimum inoculum size is 1.50%, the cellulase activity reached a maximum of 13.503 U/mL, which was about 140% higher than that before optimization. In particular, strain B13-2 had higher cellulase production when rice straws were used as the natural carbon source. Meanwhile, the SEM pictures demonstrated that the surface of the substrate rice straws in an acidic buffer with strain B13-2 was uneven, with larger holes than in the neutral buffer after incubation. It further proved that this strain has a stronger ability to degrade cellulose under acidic conditions. The B13-2 is a kind of acidophilic cellulolytic bacteria. Therefore, it has the potential to be developed into a silage additive agent and provides a high-quality strain resource for the high-value biotransformation of agricultural waste and lays a certain foundation for the sustainable development of agricultural cultivation.

Novel bio-catalytic degradation of endocrine disrupting compounds in wastewater.

Against the backdrop of towering ecological health implications of estrogen pollution and the inefficacies associated with cost-intensive treatment techniques, this study recorded the earliest attempt of developing an inexpensive bacterial laccase-based biocatalysts for biodegradation of EDCs (Endocrine disrupting compounds), particularly estrogens. First, a central composite design was used to investigate the interactive effects of pH (6.0-8.0), inoculum size (100-500 U/mL), and copper (Cu) (25-75mg/L) on laccase activity and estrogen degradation respectively. Thereafter, biocatalysts was synthesized comprising laccase and glass beads or silver impregnated clay granules (SICG), which was further used to treat estrogen infused aquatic matrices under different reaction conditions. Maximum laccase activities and estrogen removal for the two tested laccases were 620 U/mL (85.8-92.9%) and 689.8U/mL (86.8-94.6%) for Lysinibacillus sp. BP1 and Lysinibacillus sp. BP2, respectively, within 72h, under conditions of optimal inoculum size and/or Cu concentration. Apart from a higher estrogen removal rate compared to free laccased, the biocatalysts were more resistant to temperature, pH and other environmental perturbations, and had enhanced storage ability and reusability. In comparison to clay, beads had a higher potential for recyclability and were more stable under certain experimental factors such as pH, reuse, and temperature, as well as storage conditions. Immobilized enzymes were able to remove 100% of E2, as well as over 90% of E1 and EE2, in 24h, indicating that they could be scaled up to benchtop bioreactor levels.

Fermentative production of 2,3-Butanediol using bread waste – A green approach for sustainable management of food waste

Bread is Europe’s most wasted food, and the second most wasted food after potatoes in UK. Bread waste (BW) is a clean source of high-quality fermentable sugars. In this study, the potential of Enterobacter ludwigii to accumulate 2,3-butanediol (BDO) from BW was evaluated. Initially, the optimal inoculum size and yeast extract concentration were determined, followed by extraction of sugars from BW using acid and enzymatic hydrolysis. A glucose yield of 330–530 g/kg BW was obtained, and the sugars released were utilised for BDO production by E. ludwigii. The fed-batch cultivation using pure glucose and glucose rich hydrolysates from acid and enzymatic hydrolysis resulted in BDO titres of 144.5, 135.4, and 138.8 g/L, after 96 h, with yield of 0.47, 0.42 and 0.48 g/g yield, respectively. The innovation of the work is valorisation of BW to BDO with a circular biorefining approach and thus, reducing BW disposal and associated environmental burden.

Yeasts from Chinese strong flavour Daqu samples: isolation and evaluation of their potential for fortified Daqu production

In total, 16 yeast were isolated from Chinese strong flavour Daqu samples and underwent RAPD analysis and identification. Totally, 11 different species were identified among these isolates including Saccharomyces cerevisiae, Hanseniaspora vineae, Pichia kluyveri, Trichosporon asahii, Wickerhamomyces anomalus, Kluyveromyces lactis, Yarrowia lipolytica, Wickerhamomyces mori, Galactomyces geotrichum, Dabaryomyces hansenii, and Saccharomyces kudriavzevii. To understand the impact of these yeast strains on the quality and flavour of Daqu, we then assessed volatile compounds associated with Daqu samples fermented with corresponding strains. These analyses revealed strain YE006 exhibited the most robust ability to produce ethanol via fermentation but yielded relatively low quantities of volatile compounds, whereas strain YE010 exhibited relatively poor fermentation efficiency but produced the greatest quantity of volatile compounds. These two yeast strains were then utilized in a mixed culture to produce fortified Daqu, with the optimal inoculum size being assessed experimentally. These analyses revealed that maximal fermentation, saccharifying, liquefying, and esterifying power as well as high levels of volatile compounds were achieved when using a 2% inoculum composed of YE006/YE010 at a 1:2 (v/v) ratio. When the liquor prepared using this optimized fortified Daqu was compared to unfortified control Daqu, the former was found to exhibit significantly higher levels of flavour compounds and better sensory scores. Overall, our findings may provide a reliable approach to ensuring Daqu quality and improving the consistency and flavour of Chinese strong-flavour liquor through bioaugmentation.

Optimization of Bio-Calcification Process for a Newly Isolated Urease Producing Bacterial Strain Advenelle sp. AV1

Bio-calcification is a natural phenomenon catalyzed by the urease enzyme, which is produced by a wide range of bacterial strains. The bio-calcification process relies on several physicochemical factors like pH, Ca2+, inoculum size (serve as a nucleation site), temperature, etc. In this study, seven urease-producing bacteria (BS-1-BS-7) were isolated from the garden soil of the two locations and the soil collected from a cave located at Sahastradhara, Dehradun Uttarakhand, India. These isolates were tested for urease activity and CaCO3 precipitation. Among the bacterial isolates, BS-6 produced the maximum ammonium ions and CaCO3 precipitate (14.6 mg/50 ml) and therefore it was selected for the optimization study. The two important factors – inoculum size (4%, 12%, and 20%; OD value 1.2 at 600 nm) and CaCl2 concentration (25, 50, and 100 mM) were optimized for bio-calcification process (CaCO3 precipitation). The optimum inoculum size and CaCl2 concentration for the CaCO3 precipitation by the isolate BS-6 were found to be 12% and 50 mM, respectively. Two-way ANOVA (analysis of variance) indicates that both factors, inoculum size and CaCl2 concentration significantly (p < 0.05) affect the CaCO3 precipitation. The present study signifies the role of Ca2+ and inoculum size in the bio-calcification process. The selected bacterial strain BS-6 was further identified as a novel strain Advenelle sp. AV1 based on the 16S rRNA sequencing. This is the first report that shows Advenelle sp. AV1 as urease producing and bio-calcite forming bacteria.

Production and application of natural food pigments by Monascus ruber using potato chips manufacturing wastes

This work was established for using potato chips manufacturing wastes as a substrate for the production of food colorant pigments by Monascus ruber Went AUMC 5705, then it was utilized individually for coloring some food products (drops sweets). The effects of different environmental and nutritional factors were studied in solid state fermentation (SSF). The maximum concentrations of red, orange, and yellow pigments produced by M. ruber were 147.3, 179.6 and 221.7 U/g of dry fermented materials, respectively. The optimum conditions for pigments production were determined to be 50%, 6.5, 3 % and 15 days, for the initial moisture content, pH, (NH4)2SO4 , and incubation period, respectively. Moreover, the optimum inoculum size, particle size of potato chips and fermentation temperature, were determined to be 81×104 spores/10g dry substrate, 1.5 mm and 30 °C under dark condition, respectively. Then, the pigments mixture was separated into red, orange and yellow water insoluble pigments that used as coloring agents of drops sweets flavoured with fruits odours. This study revealed that potato chips wastes are an innovative raw material for pigments production by M. ruber in SSF.

Swainsonine producing performance of Alternaria oxytropis was improved by heavy-ion mutagenesis technology.

Swainsonine, an indolizidine alkaloid, is a promising anti-tumorigenic compound. Biological production of swainsonine was prospective, but the low swainsonine yield of wild type Alternaria oxytropis limited its production on a large scale. In present work, a stable A. oxytropis mutant UO1 with swanisonine yield of 14.84% higher than the wild-type strain was successfully obtained after heavy-ion irradiation. The A. oxytropis mutant UO1 and original wild-type strain were futher evaluated for SW concentrations under different factors. Results showed that the optimum culture temperature was 25°C. The optimum initial medium pH was 6.5 and the optimum inoculum size was 2mL per 200mL. Addition of the biosynthetic precursor L-pipecolic acids and L-lysine appropriately could increase the SW synthesis. These findings provided a theoretical basis and scientific data for the industrial production of swainsonine.

Removal of the fishy malodor from Bangia fusco-purpurea via fermentation of Saccharomyces cerevisiae, Acetobacter pasteurianus, and Lactobacillus plantarum.

The present study aims to evaluate the deodorization of Bangia fusco-purpurea using microorganism fermentation with commercial starter cultures of Saccharomyces cerevisiae, Acetobacter pasteurianus, and Lactobacillus plantarum. The results showed the fermentation with S. cerevisiae, A. pasteurianus, and L. plantarum resulted in significantly decreases (p<.05) of the fishy malodor in B. fusco-purpurea. Among the three strains, S. cerevisiae was the best for reducing the fishy malodor. The optimal inoculum size and fermentation time were 0.2% and 4hr, respectively. After the fermentation with the S. cerevisiae, the content of 1-octen-3-ol, (E)-2-octen-1-ol, hexanal, non-(2E)-enal, (E,E)-2,4-decadienal, 3,5-octadien-2-one, and 2-pentyl-furan were hard to be detected in the seaweed, whereas increases were observed in the concentrations of 2-butyl-1-octanol, cedrol, diisobutyl phthalate, and 2,4-di-t-butylphenol. The odor active value analysis indicated the removal of fishy odor was related to the reduction, dehydrogenation, and deformylating oxygenation of hexanal, nonanal, non-(2E)-enal, and (E,E)-2,4-decadienal and esterification of 1-octen-3-ol and (E)-2-octen-1-ol. Our findings provide a technical and scientific basis for the removal of fishy odor from B. fusco-purpurea. PRACTICAL APPLICATIONS: Bangia fusco-purpurea is a seaweed that can reduce the risks of cardiovascular and chronic metabolic diseases in human body. However, the seaweed has a strong fishy malodor, which largely declines consumer's acceptance. In this study, the commercial starters of Saccharomyces cerevisiae, Acetobacter pasteurianus, and Lactobacillus plantarum were shown to reduce the fishy malodor in B. fusco-purpurea via fermentation. After the fermentation with the microorganisms especially with the S. cerevisiae, the fishy malodor significantly reduced, and the overall aroma acceptance of B. fusco-purpurea products greatly improved. Therefore, this study provides a technical basis for the removal of fishy odor from B. fusco-purpurea and processing value-added products from it and facilitating its health benefits for human.

Antifungal effect of volatile organic compounds produced by Streptomyces salmonis PSRDC-09 against anthracnose pathogen Colletotrichum gloeosporioides PSU-03 in postharvest chili fruit.

Application of volatile organic compounds (VOCs) from Streptomyces salmonis PSRDC-09 (VOCs PSRDC-09) grown on sterile wheat seeds against chili anthracnose pathogen was investigated in vitro and in vivo. Among 10 isolates of Colletotrichum species tested, Colletotrichum gloeosporioides PSU-03 was selected as the most aggressive anthracnose pathogenic strain on chili fruit against VOCs produced by Streptomyces species. Among 11 isolates, the strain PSRDC-09 exhibited the highest antifungal activity and was identified as S. salmonis PSRDC-09. The antagonistic mechanism of the VOCs PSRDC-09 on morphological of C. gloeosporioides PSU-03, observed by scanning electron microscope (SEM), revealed the irregular distortions in the fungal hyphae. The effect of inoculum size and spore concentration of S. salmonis PSRDC-09 prepared as a wheat seed inoculum on the suppression of C. gloeosporioides PSU-03 was studied both in vitro and on chili fruit. The optimum inoculum size (45g 0·31l-1 ) and spore concentration (107 spores per ml) of the wheat seed culture of S. salmonis PSRDC-09 exhibited the complete suppression (100% inhibition) on C. gloeosporioides PSU-03. The optimum fumigation period of the VOCs PSRDC-09 (45g 1·38l-1 ) was found to be 24h. Based on gas chromatography-mass spectrometry (GC-MS) analysis, 14 major VOCs (produced by the strain PSRDC-09) were detected and l-linalool was the main volatile component. The results indicated that the VOCs from S. salmonis PSRDC-09 could effectively control the chili anthracnose disease caused by C. gloeosporioides. These findings suggest that S. salmonis PSRDC-09 may have the potential to become a promising biofumigant for biocontrol of chili anthracnose disease in the postharvest system.

Biosorption performance and cell surface properties of a fungal-based sorbent in azo dye removal coupled with textile wastewater

In this work, the biosorption ability of Sarocladium sp. dried biomass to remove Remazol Black dye has been studied. Optimum inoculum size and initial dye concentration were determined, and the salinity effect on the dye removal was evaluated. In the following, kinetic and isotherm of the adsorption were studied, and the adsorbent characteristics were determined using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, zeta potential, and Brunauer–Emmett–Teller analysis. Based on the results, maximum and minimum dye removal was determined at 1000 and 200 mg L−1 of Remazol Black dye as 54.39 and 24.02 mg g−1, respectively. Among the various azo dyes including Reactive yellow 145, Reactive blue 222, Reactive red 43, Direct blue 21, and Acid blue 161, dye removal capability of 87.96–97.43% was obtained. The solution salinity showed positive effect on the biosorption process. The biomass pretreatment with calcium nitrate enhanced the removal capacity by 70.48% and the maximum reduction in dye removal (− 61%) was obtained when the fungal biomass was treated by sodium hydroxide. Biosorption kinetic follows the first-pseudo-order model, and the obtained data best fits both Langmuir and Freundlich isotherm models. The maximum adsorption capacity of dried biomass for dye removal was 58.48 mg g−1. Based on FTIR, zeta potential value and pretreatment results, Yoshida H-binding, dipole–dipole H-binding, π–π and n–π interactions were probably involved in the dye adsorption process. The results showed that biomass has a high potential for different dyes adsorption from real textile wastewater. The present study declares the high potential of Sarocladium sp. dried biomass as an effective and inexpensive biosorbent which can be used for bio-treatment of effluents with multi-dyes.

Capitalization of sea buckthorn waste by fermentation: Optimization of industrial process of obtaining a novel refreshing drink

This paper provides a solution for the management of waste from the sea buckthorn (Hippophae rhamnoides L.) processing industry. The application of fermentation technology on this practically nonvalue sea buckthorn material leads to the attainment of a novel beverage with functional properties. The optimum production conditions of a fermented low-alcoholic drink from sea buckthorn waste by Saccharomyces cerevisiae were determined. Response surface methodology coupled with Box–Behnken design was employed for the optimization studies. The study revealed an optimum inoculum size of 0.2% at fermentation temperature of 23.3 °C for 72 hr for obtaining a 3% of ethanol sea buckthorn beverage, with no microbial load of the samples during fermentation process. Quadratic polynomial models could predict and describe the physico-chemical responses of the final product. Furthermore, the high-performance liquid chromatography and photochemiluminescence assays revealed the functional properties of the obtained beverage, which had an important amount of phenolic compounds and high antioxidant activity. Practical applications This study proves that sea buckthorn waste can act as a suitable substrate for fermentation, resulting in a novel sea buckthorn beverage, which is not only refreshing and energizing (due to its content in carbon dioxide and low level of ethanol), but also healthy. Mathematical models described are of high importance for process conditions selection and response prediction in industrial environment. Therefore, this study provides useful information for the fermented drinks industry, helping beverage processing industries achieve optimum yield in low alcoholic wine production using sea buckthorn waste as sole substrate.

Enhanced (R)-2-(4-Hydroxyphenoxy)Propionic Acid Production by Beauveria bassiana: Optimization of Culture Medium and H2O2 Supplement Under Static Cultivation.

(R)-2-(4-hydroxyphenoxy)propionic acid (HPOPA) is a key intermediate for the preparation of aryloxyphenoxypropionic acid herbicides (R-isomer). In order to improve the HPOPA production from the substrate (R)-2-phenoxypropionic acid (POPA) with Beauveria bassiana CCN-A7, static cultivation and H2O2 addition were attempted and found to be conducive to the task at hand. This is the first report on HPOPA production under static cultivation and reactive oxygen species (ROS) induction. On this premise, the cultivation conditions and fermentation medium compositions were optimized. As a result, the optimal carbon source, organic nitrogen source, and inorganic nitrogen source were determined to be glucose, peptone, and ammonium sulfate, respectively. The optimal inoculum size and fermentation temperature were 13.3% and 28°C, respectively. The significant factors including glucose, peptone, and H2O2, identified based on Plackett-Burman design, were further optimized through Central Composite Design (CCD). The optimal concentrations/amounts were as follows: glucose 38.81 g/l, peptone 7.28 g/l, and H2O2 1.08 ml/100 ml. Under the optimized conditions, HPOPA titer was improved from 9.60 g/l to 19.53 g/l, representing an increase of 2.03- fold. The results obtained in this work will provide novel strategies for improving the biosynthesis of hydroxy aromatics.

Biodegradation of endocrine disruptor Bisphenol A by Pseudomonas putida strain YC-AE1 isolated from polluted soil, Guangdong, China

BackgroundBisphenol A is an important organic chemical as an intermediate, final and inert ingredient in manufacturing of many important products like polycarbonate plastics, epoxy resins, flame retardants, food–drink packaging coating, and other. BPA is an endocrine disruptor compound that mimics the function of estrogen causing damage to reproductive organs. Bacterial degradation has been consider as a cost effective and eco-friendly method for BPA degradation compared with physical and chemical methods. This study aimed to isolate and identify bacterial strain capable to degrade and tolerate high concentrations of this pollutant, studying the factors affecting the degradation process and study the degradation mechanism of this strain.ResultsYC-AE1 is a Gram negative bacterial strain isolated from soil and identified as Pseudomonas putida by 16S rRNA gene sequence and BIOLOG identification system. This strain found to have a high capacity to degrade the endocrine disruptor Bisphenol A (BPA). Response surface methodology using central composite design was used to statistically optimize the environmental factors during BPA degradation and the results obtained by significant model were 7.2, 30 °C and 2.5% for optimum initial pH, temperature and inoculum size, respectively. Prolonged incubation period with low NaCl concentration improve the biodegradation of BPA. Analysis of variance (ANOVA) showed high coefficient of determination, R2 and Adj-R2 which were 0.9979 and 0.9935, respectively. Substrate analysis found that, strain YC-AE1 could degrade a wide variety of bisphenol A-related pollutants such as bisphenol B, bisphenol F, bisphenol S, Dibutyl phthalate, Diethylhexyl phthalate and Diethyl phthalate in varying proportion. Pseudomonas putida YC-AE1 showed high ability to degrade a wide range of BPA concentrations (0.5–1000 mg l− 1) with completely degradation for 500 mg l− 1 within 72 h. Metabolic intermediates detected in this study by HPLC-MS were identified as 4,4-dihydroxy-alpha-methylstilbene, p-hydroxybenzaldeyde, p-hydroxyacetophenone, 4-hydroxyphenylacetate, 4-hydroxyphenacyl alcohol, 2,2-bis(4-hydroxyphenyl)-1-propanol, 1,2-bis(4-hydroxyphenyl)-2-propanol and 2,2-bis(4-hydroxyphenyl) propanoate.ConclusionsThis study reports Pseudomonas putida YC-AE1 as BPA biodegrader with high performance in degradation and tolerance to high BPA concentration. It exhibited strong degradation capacity and prominent adaptability towards a wide range of environmental conditions. Moreover, it degrades BPA in a short time via two different degradation pathways.

Comparison of citric acid production from Aspergillus niger in solid and suspension state fermentation

Aim: Due to huge demand of citric acid, there is a need to find alternatives for its efficient production either using low-cost substrates or by improving the potency of the fermentation microorganisms. Materials and Methods: In this study, microbial production of citric acid was performed by Aspergillus niger. Solid and suspension state fermentation was carried out using biodiesel waste, i.e. the oilseed cake of Pongamia pinnata (honge) as a substrate for the comparative study of citric acid production using A. niger. After the estimation, the concentration of citric acid was found to be more in suspension state fermentation than in solid state. Hence, the further analysis was carried out using suspension culture. In the first stage, weight was varied, and the optimum weight was found out to be 12.5 g. Then keeping this optimum weight as constant, the inoculum size was varied, also keeping the optimum pH 6 and temperature 32°C constant. The rpm of suspension state was kept 100. Through this, optimum inoculum size was obtained. Results and Discussion: The yield of citric acid in solid state fermentation (SSF) was found to be 4.74 mg in 12.5 g of substrate and suspension state was 9.6 mg/ml. Conclusion: Suspension state fermentation method gives a higher yield of citric acid using oil seed cake as the substrate from A. niger than SSF method. The highest yield of 10.43 mg/ml of citric acid was obtained by taking substrate weight 12.5 g and inoculum size 275*104 spores/ml by suspension state fermentation method.

Integrated lignocellulosic bioprocess for co-production of ethanol and xylitol from sugarcane bagasse

Economics of cellulosic ethanol production could be supported by high-value chemicals co-production, e.g. xylitol, which has high market value in food and pharmaceutical industries. Herein, we present an integrated sugarcane bagasse processing for the co-production of ethanol and xylitol from cellulose and hemicellulose, respectively. Process integration comprised pretreatment followed by separation of hemicellulosic hydrolysate and pretreated cellulose, in combination with enzymatic hydrolysis and fermentation. Saccharomyces cerevisiae was used for ethanol production in a simultaneous saccharification and fermentation process of pretreated cellulose, and Candida tropicalis was selected for xylitol fermentation of hemicellulosic hydrolysate. Batch process parameters were systematically optimized resulting in 7.5 FPU/g optimal enzyme load, 0.03 g/L and 0.035 g/g optimal inoculum size, 89 h−1 optimal kLa and 54 g/g optimal sugar-to-nitrogen ratio. Finally, fed-batch strategy was accomplished yielding maximum concentrations of ethanol by S. cerevisiae and xylitol by C. tropicalis at 56.1 g/L and 24.0 g/L, respectively. Of the total glucose and xylose available in bagasse, the product yield of 0.44 g/g (ethanol) and 0.50 g/g (xylitol) were reached. Economic analysis revealed that the incorporation of xylitol with ethanol in an integrated biorefinery together with fed-batch strategy for high-titer product could improve profitability by 2.3-folds compared to base case of cellulosic ethanol production. Hence, this integrated biorefinery for co-production could be attractive to current cellulosic ethanol for advancing economic feasibility.

Protein Production Through Microbial Conversion of Rice Straw by Multi-Strain Fermentation.

Multi-strain mixed fermentation can provide a relatively complete lignocellulosic enzyme system compared with single-strain fermentation. This study was firstly to screen strains which have a strong ability to hydrolyse rice straw (RS) enzymatically and enrich true protein (TP). Then, the conditions in the process of SSF, including the optimum inoculum size of mixed strains, inoculation ratio, and different inoculation time of N. crassa 14-8, were optimized. The experimental results showed that the highest TP content could be obtained by using N. crassa 14-8, C. utilis, and P. chrysosporium as mixed strains, and 5mM Mn2+ and 50mM veratryl alcohol were used as inducers of lignin peroxidase (LiP) to improve the efficiency of enzymatic hydrolysis. When N. crassa 14-8 was inoculated 1day later than P. chrysosporium, the total inoculum size was 10%, and the optimum ratio of N. crassa 14-8 to P. chrysosporium was 1:2, the maximum TP yield (8.89%) was obtained, with 123.37% of its increase rate. This work proposed a technique with potential application in large-scale feedstuff protein conversion.

Hyperproduction of exopolysaccharides by submerged mycelial culture of Ganoderma lucidum using a solid seed grown in fine-powder of wheat bran and in vitro evaluation of the antioxidant activity of the exopolysaccharides produced.

To facilitate Ganoderma lucidum submerged culture and obtain high productivity, a fine powder of wheat bran was used to grow the fungus for solid-state fermentation and as solid seed for its submerged cultures. The results indicated that the optimal inoculum size was low, being 0.75g in 250mL-sized flasks containing 80mL medium. The maximal exopolysaccharide concentration and biomass produced was 0.74 and 14.71g/L, respectively, which is considerably higher than that obtained with the commonly used mycelial pellet liquid seed (0.47 and 8.56g/L, respectively). The EPS and biomass productivity of the solid seed cultures decreased only slightly, even after a 6-month storage period. EPS produced showed higher antioxidant activity compared with that produced in the liquid seed cultures. The developed solid seed can serve as a ready-to-use inoculum for long-term use in G. lucidum submerged culture for the hyperproduction of highly bioactive EPS and biomass.

Repeated batch fermentation for photo-hydrogen and lipid production from wastewater of a sugar manufacturing plant

Hydrogen and lipid production from sugar manufacturing plant wastewater (SMW) by Rhodobacter sp. KKU-PS1 were investigated. Aji-L (i.e., a waste from the process of crystallizing monosodium glutamate) was used as nitrogen source. Batch fermentation was conducted in 300 mL serum bottles with the working volume of 180 mL to investigate the optimal inoculum size by varying the initial inoculum concentration from 0.23 to 0.92 gCDW/L. The photo-fermentation was conducted at an initial pH 7.0 and 25.6 °C with continuously light illumination at 7500 lux. The optimal inoculum size of 0.77 gCDW/L gave the hydrogen production rate (Rm) and lipid production of 5.24 mL H2/L.h and 407 mg lipid/L, respectively. The hydrogen production from SMW was further examined in 1.7-L photo-bioreactor with the working volume of 1.2-L using the optimal condition from batch experiment. A photo-bioreactor yielded 1.73 times higher Rm than that obtained from the fermentation in serum bottles with a greater lipid production of 424 mg lipid/L. Hydrogen production from SMW in the repeated-batch fermentation was further studied by varying the medium replacement ratios of 25, 50–75%. A maximum biomass and lipid concentration of 2.83 gCDW/L and 685 mg lipid/L, respectively were achieved at a medium replacement ratio of 75%. C18:1 (51.2%), C18:0 (24.9%) and C16:0 (9.1%) were found as the major free fatty acid. Lactic acid followed by propionic, acetic and butyric acids containing in SMW were the suitable carbon source for biomass production of KKU-PS1.

Isolation, characterization and identification of extracellular enzyme producer Bacillus licheniformis from municipal wastewater and evaluation of their biodegradability

In the present investigation, a total of 34 bacterial isolates were isolated from municipal wastewater and sludge samples. Out of 34, 5 isolates were selected based on their growth on wastewater agar medium and were identified on the basis of morphological, cultural and biochemical tests. The enzyme production study showed that all the isolates were able to produce lipase and protease while one isolate (NW1D) showed amylase production. The bioremediation potential of these enzymes producing bacteria was investigated and the results suggest that the isolate NW6 was most efficient for bioremediation and showed reduction in biochemical oxidation demand (BOD), chemical oxidation demand (COD), nitrate and phosphate by 50.65%, 20%, 56.25% and 31.13% respectively after 72h. Further, the NW6 isolate identified as Bacillus licheniformis by 16S rRNA sequencing and was optimized for different parameters to achieve effective results. The results showed that overall optimum inoculum size, retention time and agitation speed for NW6 were 10% (v/v), 96h and 200rpm respectively. The reduction in BOD, COD, nitrate and phosphate was found to be 54.55%, 36%, 24.83% and 26.42% respectively with 10% inoculum size. At 96h retention time with 10% inoculum, BOD, COD, nitrate and phosphate reduction was 69.16%, 42.5%, 49.89% and 39.62% respectively. The reduction in BOD, COD, nitrate and phosphate was found to be 72.08%, 51%, 51.87% and 31.13% respectively at 200rpm with 10% inoculum. Further, the NW6 may find application in municipal wastewater treatment to prevent water pollution as well as a potential enzyme production.