Bioconversion of De-Oiled Rice Bran (DORB) Hemicellulosic Hydrolysate into Ethanol by Pichia stipitis NCM3499 under Optimized Conditions

Author(s):  
Anuj Kumar Chandel ◽  
Mangamoori Lakshmi Narasu ◽  
Ravinder Rudravaram ◽  
Ravindra Pogaku ◽  
Linga Venkateswar Rao

In the present paper, parametric optimization studies were performed to determine the most influential range of process parameters for maximum ethanol production from Pichia stipitis NCIM3499 by one-at-a-time method under submerged fermentation conditions. Various parameters, such as agitation, pH of medium, temperature and different carbon sources, etc., were taken into consideration. The optimum values of these process parameters were as follows: agitation (200 rpm), pH (5.5), temperature (30°C), and semi-aerobic conditions (150 ml fermentation media in 250 ml Erlenmeyer flask). Among the different carbon substrates tested, glucose and xylose (20±0.21 g/l) showed same ethanol production (8.8±0.35 g/l) with a yield of 0.44±0.11g/g sugar utilized. These process parameters were applied for the ethanol production from de-oiled rice bran (DORB), the left over residue after extraction of oil. It was thermochemically saccharified using sulfuric acid (0.5-5.5% v/v) at 120°C for a fixed residence time of 1h. A maximum of 38.50±0.45 g/l total reducing sugars was obtained at 3.5% v/v H2SO4. This sugar syrup was detoxified by overliming with calcium hydroxide and subsequently fermented with P. stipitis NCIM3499 under the optimized conditions. After 72 h of incubation, DORB hydrolysate (33.50±0.44g/l total reducing sugars) showed maximum ethanol production (12.47±0.26g/l) with the yield 0.42±0.021g/g and fermentation efficiency of 81.74±0.55%. To the best of our knowledge, this is the first report on ethanol production from de-oiled rice bran using P. stipitis NCIM3499.

ENERGYO ◽  
2018 ◽  
Author(s):  
Anuj Kumar Chandel ◽  
Mangamoori Lakshmi Narasu ◽  
Ravinder Rudravaram ◽  
Ravindra Pogaku ◽  
Linga Venkateswar Rao

Author(s):  
Chandrasekhar Gajula ◽  
Anuj Kumar Chandel ◽  
Radhika Konakalla ◽  
Ravinder Rudravaram ◽  
Ravindra Pogaku ◽  
...  

Groundnut shell (GS), after separation of pod, is readily available as a potential feedstock for production of fermentable sugars. The substrate was delignified with sodium sulfite. The delignified substrate released 670 mg/g of sugars after enzymatic hydrolysis (50°C, 120 rpm, 50 hrs) using commercial cellulases (Dyadic® Xylanase PLUS, Dyadic Inc. USA). The groundnut shell enzymatic hydrolysate (45.6 g/L reducing sugars) was fermented for ethanol production with free and sorghum stalks immobilized cells of Pichia stipitis NCIM 3498 under submerged cultivation conditions. Immobilization of yeast cells on sorghum stalks were confirmed by scanning electron microscopy (SEM). A maximum of ethanol production (17.83 g/L, yield 0.44 g/g and 20.45 g/L, yield 0.47 g/g) was observed with free and immobilized cells of P. stipitis respectively in batch fermentation conditions. Recycling of immobilized cells showed a stable ethanol production (20.45 g/L, yield 0.47 g/g) up to 5 batches followed by a gradual downfall in subsequent cycles.


Author(s):  
Seong Ju Kim ◽  
Tae Hyun Kim ◽  
Kyeong Keun Oh

In order to produce bioethanol from yellow poplar sawdust without detoxification, deacetylation (mild alkali treatment) was performed with aqueous ammonia solution. To select the optimal conditions, deacetylation process was carried out using different conditions: NH4OH loading (2–10% (w/v)) and solid-to-liquid ratio (1:4–10) at 121 °C for 60 min. In order to assess the effectiveness of deacetylation, fractionation of deacetylated yellow poplar sawdust was performed using dilute acid (H2SO4, 0.5–2.0% (w/v)), reaction temperature (130–150 °C) and time (10–80 min). The toxicity-reduced hemicellulosic hydrolysates that were obtained through a two-step treatment at optimized conditions were fermented using Pichia stipitis for ethanol production, without any further detoxification. The maximum ethanol production was 4.84 g/L, corresponding to a theoretical ethanol yield of 82.52%, which is comparable to those of intentionally made hydrolyzates as controls.


RSC Advances ◽  
2015 ◽  
Vol 5 (125) ◽  
pp. 103265-103275 ◽  
Author(s):  
Mood Mohan ◽  
Robinson Timung ◽  
Narendra Naik Deshavath ◽  
Tamal Banerjee ◽  
Vaibhav V. Goud ◽  
...  

Subcritical water (SCW) treatment has gained enormous attention as an environmentally friendly technique for organic matter and an attractive reaction medium for a variety of applications. In the current work the process parameters were optimized by RSM model.


BioResources ◽  
2018 ◽  
Vol 14 (1) ◽  
pp. 592-606

Effects of acid, alkali, ionic liquid (IL), and microwave-alkali pretreatments on cellulosic water hyacinth (WH) were investigated based on the total reducing sugars (TRS) and ethanol production. For the first time, IL pretreatment with (1-Ethyl-3-methylimidazolium acetate ([EMIM][Ac]) was used for WH, and the efficiency was compared with the other methods. Cellulase and Saccharomyces cerevisiae were fermented together for 72 h. Based on the results, all pretreatment methods effectively increased the sugar content as well as the ethanol yield. Untreated WH had 25 ± 1.5 mg/g of TRS, which was increased to 157 ± 8.2 mg/g, 95 ± 3.1 mg/g, 51 ± 4.2 mg/g, and 45 ± 2.6 mg/g via alkali, microwave-alkali, acid, and IL pretreatments, respectively. The highest TRS level of 402 mg/g was obtained in 24 h and 6.2 ± 0.4 g/L of ethanol in 48 h of fermentation with the alkali-treated WH. The ethanol production was followed by other treatment methods of WH in the order of microwave-alkali, acid, and IL. The results indicated that the ethanol production from WH was related to the type of pretreatment as well as the TRS production.


Author(s):  
Girisha Malhotra ◽  
Shilpa S. Chapadgaonkar

Abstract Background Xylanase is one of the widely applied industrial enzymes with diverse applications. Thermostability and alkali tolerance are the two most desirable qualities for industrial applications of xylanase. In this paper, we reveal the statistical Taguchi optimization strategy for maximization of xylanase production. The important process parameters pH, temperature, concentration of wheat bran, and concentration of yeast extract were optimized using the Taguchi L8 orthogonal array where the 4 factors were considered at 2 levels (high and low). Results The optimized conditions given by model were obtained as follows: (i) pH 6, (ii) culture temperature 35 °C, (iii) concentration of xylan 2% w/v, (iv) concentration of wheat bran 2.5% w/v. The production was scaled upto 2.5 L bioreactor using optimized process parameters. A high xylanase titer of 400 U/ml could be achieved in less than 60 h of culture in the reactor. Conclusion Optimization was successful in achieving about threefold increase in the yield of xylanase. The optimized conditions resulted in a successful scale up and enhancement of xylanase production.


2010 ◽  
Vol 171-172 ◽  
pp. 261-265
Author(s):  
Zhuang Zuo ◽  
Xiu Shan Yang

Corn stover was pretreated using different soaking conditions at mild temperature. Among the tested conditions, the best was 1% NaOH+8% NH4OH,50°C,48 h, Solid-to-liquid ratio 1:10. The results showed that soaking pretreatment achieved 63.6% delignification, retained the xylan and glucan. After enzymatic hydrolysis, conversion rates of xylan and glucan were 70.9% and 78.5%, respectively. The pretreated filtration re-soaking cause 52.7% xylan and 65.0% glucan conversion. NaOH+NH4OH treatment can be performed under mild conditions, gives a good buffering effect, low carbohydates degradation and extensive removal of lignin. Additionally, simultaneous saccharification and fermentation was conducted with pretreated corn stover to assess the ethanol production. For the whole process, 0.15g ethanol /g corn stover was achieved using Saccharomyces cerevisiae Y5, and 0.19g ethanol /g corn stover when using Pichia stipitis.


1992 ◽  
Vol 26 (5-6) ◽  
pp. 1047-1055 ◽  
Author(s):  
N. F. Y. Tam ◽  
Y. S. Wong ◽  
G. Leung

Laboratory-scale studies were undertaken to examine the effects of easily-biodegradable organic substances upon the nutrient removal by a simulated sequencing batch reactor (SBR). The fill and react period of the SBR was 14 hours, including an instant fill, 7 hours aeration, 4 hours anoxic and 3 hours aeration period. Three kinds of commonly used carbon sources, namely methanol, glucose and sodium acetate, at the concentrations equivalent to theoretical COD values of 50, 100 and 150 mg O2 l-1 were added to each reactor prior to the anoxic stage. The results showed that the concentration of NH4+-N dropped from its initial 50 to 18 mg l-1 (64 % removal) during the first aeration period, with the NO3−-N content increased from 2 to 33 mg l−1. A 60% depletion of COD was also recorded in this period. Denitrification occurred during the anoxic period, higher amount of NO3−1-N was removed in the reactors supplemented with carbon substrates at the concentrations of 100 and 150 mg l-1. The final inorganic nitrogen content was less than 5 mg l-1 in the reactor supplemented with 150 mg l-1 sodium acetate. Simultaneous removal of phosphorus was reported in reactors supplied with high concentration of sodium acetate. In these reactors, large amount of P was released during the anoxic/anaerobic period but the released P was taken up by bacterial cells in the subsequent aeration stage, and the final P content was less than 1.5 mg l-1 (84 % removal was achieved). Among the three carbon sources used, sodium acetate was the most efficient and effective source in removing wastewater nutrients, followed by methanol, and glucose was the least reliable substrate.


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