Journal of Bioprocessing & Biotechniques

In the present study, ten waste nutrient sources namely potato peels, banana peels, cow dung, press mud, molasses, bagasse hydrolysate, glycerol, succinate, cheese whey and cyanobacterial spent media extract were used for the growth of five potential green algal species namely C. reinhardtii, S. obliquus, C. vulgaris, C. minutissima and B. braunii. The nutrient extracts were prepared so as to not interfere with algal biomass harvesting. The effect of waste nutrients was investigated especially on the biomass and lipid accumulation in algae. The lipids so produced were quantified gravimetrically and analyzed using GC-MS and proton NMR. As a result, all the microalgal species showed enhancement in their growth and lipid production with most of the waste nutrients. C. reinhardtii showed maximum increase in lipid production with potato peels (89%) and banana peels (90%). However, a maximum of 130% increase in biomass content was observed in C. vulgaris with glycerol supplementation. 1H-NMR and GC-MS studies showed that carbon supplementation leads to reduction in the aromaticity of lipids and increase in the C16 and C18 fatty acids fractions, respectively rendering it more suitable for biodiesel production.

In Asia, rice straw residue left in fields after harvest is often burned which causes air pollution or anaerobically digested in the rice patty moist soil to yield methane a greenhouse gas. Effective and efficient process strategies are needed to convert straw into fuels and feedstock’s which do not harm the environment. As a result, this study was undertaken to liquefy Japanese rice straw (RS) an abundant agricultural residue into a liquid after pre-treatment by ball-milling at various temperatures and develop a bioprocess model. Specifically, RS was ball milled into 75-100 μm size particles at temperatures of 60°C, 25°C, and -196°C (cryogenically) and dissolved by heating in 1-ethyl-3- methylimidazolium acetate [Emim][OAc] at different temperatures between 120° 140° and 160°C to understand the interactions between the process parameters. The milled RS powder particles were characterized by FTIR, XRD, BET analyzer and dissolution follow using optical microscopy. The particle dissolution was analyzed by measuring the particle light intensity ratio and particle cross-sectional area as a function of heating time. Higher milling temperature leads to amorphization of the RS cellulose accelerating dissolution. Measurement of the particle light intensity ratio was used to estimate the rice straw particles dissolution endpoint. A particle dissolution model indicated that ball milling temperature and [Emim][OAc] heating temperature strongly interacts influencing the dissolution time. To dissolve RS in [Emim][OAc] quickly, it important to reduce the crystallinity of the cellulose and increase the particle surface area by milling at higher temperature. It is believed this model would have applications to other biomass dissolution processes.

Microbial Fuel Cell (MFC) can be a great demand for waste water treatment in future. Alternatively, the increasing demand of energy can be fulfilled by this technique in the future if the performance of MFC is improved. In this paper, a MFC was constructed by using graphite felt immobilized with neutral red as anode and a platinum coated platinum wire as cathode. Analyte used was municipal wastewater and catholyte was phosphate buffer of pH 7. The wastewater contained 1.457 mg/l of Ammonical Nitrogen, 33.363 mg/l of COD, 0.537 mg/l of total Phosphorus, 0.105 mg/l of reducing sugar and 0.139 mg/l of Nitrite nitrogen. The mixed culture of organism dominantly present in the wastewater was used in MFC. The result was found to be effective when cellulose acetate was used as membrane compared to the Nafion membrane. The COD of wastewater was reduced by 69.96% when MFC was run for five days with cellulose acetate membrane. The maximum power generated was 24.45 W/m3 when 1% H2O2 was supplied as a source of oxygen in the cathode compartment. The result indicates microbial fuel cell technology to be a new approach for wastewater treatment as it produces sustainable clean energy by minimizing COD level.

Probiotics containing autochthonous Lactic Acid Bacteria (LAB) as local treatment in the Bovine Reproductive Tract (BRT) was proposed as a sustainable alternative to prevent outcome of pathogens colonization in the postpartum uterus in cows. Microencapsulation of these LABs could improve their survival during stressing conditions and promote the intimate contact between the veterinarian form and the vaginal mucosa. In this work, emulsion-ionic gelation technique was applied to encapsulate bovine LAB strains in an alginate (3%) matrix. Optical and scanning electron microscopic evaluations showed spheroidal particles (12-48 μm) with a fully charge of LAB; the average load ranged 8.98 ± 0.15 to 8.06 ± 0.21 log CFU/g. The microencapsulated lactic acid bacteria (LAB-MCs) stability was evaluated during lyophilization [in Skim Milk (SM), or Neutral Distilled Water (NDW)] and storage (at 4°C up to 90 days). SM represented a significant high protection to the lyophilization. Also, the alginate microencapsulation improved the LAB strain resistance when freeze-dried in water, comparing to known sensibility of LAB free cells. L. gasseri CRL 1412 showed similar resistance in both, NDW (0.70 ± 0.05) and SM (0.72 ± 0.05); and their microcapsules (MCs) exhibited antagonistic activity against E. coli 99/14 (pathogen from Bovine metritis) when cultured together; contrary, in co-culture with empty-MCs no inhibition was observed. To evaluate the microencapsulation process, different parameters were estimated: Encapsulation Factor (EF) (ranged between 0.76 ± 0.03 and 0.85 ± 0.08) and Encapsulating Efficiency (EE) (average EE%=75%) none significant differences (LSDFisher test, P<0.05) were observed between LAB strains. Taking account the weight of the materials, the calculated average yield was 50.5%. The standardized encapsulation conditions allowed selected L. gasseri CRL 1412-MCs as potential systems to be included in formulations to restore vaginal microbiota to prevent metritis in cows.

This paper documents a simplified process model developed in connection with the Biomass Gasification Development program at the University of Louisiana at Lafayette. The numerical solution to the set of non-linear simultaneous equations arising from the analysis was implemented using the “Solver” feature of MS Excel®. It is designed to provide a rational first-pass basis for reactor sizing and process equipment selection yet is accessible and readily modifiable by a process engineer with an average programming background. The results follow trends with respect to the important variables (temperature, feedstock composition, etc.) in general agreement with experimental data reported for well-mixed, relatively isothermal reactors such as bubbling and circulating fluidized beds. The model generally overestimates the quantitative H2/CO ratio reported for most gasifiers which results in an underestimation of the product density. However, this does not appear to have a strong influence on energy factors (e.g., the gasifier chemical energy efficiency) and is considered sufficiently accurate for initial design and selection of gasification system components.

Cellulose, a major constituent of plant cell wall, is the most abundant biological polymer on earth. The use of various cellulolytic microorganisms for the bioconversion of cellulose into value added products has attracted a worldwide attention. Hence the present work was aimed to isolate new cellulase producing microorganisms and further to investigate the effect of nutritional and process parameters on cellulase production from selected isolated culture. Out of 20 cellulase producing bacterial strains isolated during the study, Y3 isolate was found to be best for the production of cellulase enzyme. This isolate was then characterized for its morphological and biochemical characters and identified as Bacillus sp. Y3. The effect of different parameters like carbon sources, nitrogen sources, temperature, pH, inoculum concentration and incubation time was monitored with selected strain for cellulase production. The maximum FPase and CMCase activity of Bacillus sp. Y3 was 6.84 IU/mL and 7.82 IU/ mL, respectively, when the basal media of pH 7 containing CMC (1%, w/v) and peptone (1%, w/v) was inoculated with 2% (v/v) inoculum and incubated at 37°C for 96 hours at 120 rpm. The FPase (6.84 IU/mL) and CMCase activity (7.82 IU/mL) obtained after optimization was much higher than FPase (1.97 IU/mL) and CMCase activity (2.48 IU/ mL) before optimization.