Utilization Of Rice Straw Research Articles

PENGETAHUAN DAN PERSEPSI PETANI TERHADAP PENGOMPOSAN LIMBAH JERAMI PADI

The utilization of rice straw as compost is very related to farmers' knowledge on how to compost agricultural waste. Knowledge of rice straw composting owned by farmers is closely related to socialization and training obtained from field extension officers (FEO). The role of FEO in the field becomes very strategic in an effort to increase farmers' knowledge about agricultural waste treatment and its utilization so as to provide economic impact. The purpose of the research is to understand the knowledge and perception of farmers about composting rice straw. By using survey and interview methods, this research also seeks to uncover farmers' knowledge related to rice straw compost. The research was conducted in 3 sub-districts in Klungkung (Klungkung, Dawan, and Banjarangkan) during May-June 2017. The results showed that farmers do not know how to compost rice straw because only 2.25% of farmers have ever attended rice straw composting training. Dominant farmers (74.16%) view if rice straw cannot be composted. The results of interviews with FEO in the Klungkung district obtained the fact that FEO never socialized rice straw composting.

Pengetahuan Dan Persepsi Petani Terhadap Pengomposan Limbah Jerami Padi

The utilization of rice straw as compost is very related to farmers knowledge on how to compost agricultural waste. Knowledge of rice straw composting owned by farmers is closely related to socialization and training obtained from field extension officers (FEO). The role of FEO in the field becomes very strategic in an effort to increase farmers knowledge about agricultural waste treatment and its utilization so as to provide economic impact. The purpose of the research is to understand the knowledge and perception of farmers about composting rice straw. By using survey and interview methods, this research also seeks to uncover farmers knowledge related to rice straw compost. The research was conducted in 3 sub-districts in Klungkung (Klungkung, Dawan, and Banjarangkan) during May-June 2017. The results showed that farmers do not know how to compost rice straw because only 2.25% of farmers have ever attended rice straw composting training. Dominant farmers (74.16%) view if rice straw cannot be composted. The results of interviews with FEO in the Klungkung district obtained the fact that FEO never socialized rice straw composting.

FARMERS’ EXTENT OF AWARENESS IN RICE STRAW PROPER DISPOSAL AND UTIIZATION IN FARMING PRODUCTION ACTIVITIES

This study was entitled Farmers’ Extent of Awareness in Rice Straw Proper Disposal and Utilization in Farming Production Activities. This study was conducted to determine the level of awareness of the farmers in rice straw proper disposal and utilization of rice straw in farming production activities. The study used descriptive research to describe the profile of the respondents, the process of rice straw disposal, awareness of the respondents on proper disposal of rice straw, and the problems encountered by the farmers in disposing and utilizing rice straw, including their recommended solutions. The respondents were chosen through random sampling. The number of respondents was determined using Slovin’s formula, a total of 255 respondents. Descriptive analysis was used to summarize, discuss, and interpret the data. Frequency, percentage, mean, standard deviation, and Pearson’s correlation were used to analyze the data. The researcher chose the top 3 barangays that had produced the largest amount of rice in April 2016. The barangays are within Science City of Munoz, Nueva Ecija Province, Philippines namely: Barangay Catalanacan, Barangay Maligaya, and Barangay Villa Nati. The farmers of the Science City of Munoz, Nueva Ecija are highly aware of the proper disposal of rice straw. However, despite their awareness, they only moderately utilize the rice straw in farming production activities. Incorporating rice straw into the soil to use it as fertilizer for the next planting of rice is the most used strategy by the farmers to utilize the rice straw. There is a negative significant relationship between the respondents’ socio-economic profile and their awareness of proper disposal and utilization in farming production activities. Since the utilization of rice straw is laborious and requires machinery, rice straw is not fully utilized such as its use as a biofuel. The farmers need monitoring from the Department of Agriculture regarding their activities in disposing and utilizing rice straw.

POTENTIAL OF LOSS OF ORGANIC FERTILIZER IN LOWLAND RICE FARMING IN KLUNGKUNG DISTRICT, BALI

Rice straw is an abundant resource that was still seen as a waste in intensive rice cultivation. Rice straw is said to be a resource because it can be used as organic fertilizer (compost) and contains nutrients that were beneficial for crop growth and soil fertility. The fact in the field was still found that rice straw was wasted, one of which was burned. A study was conducted through a method of observation and survey involving rice paddy farmers in 3 sub-districts in the district of Klungkung, namely Banjarangkan, Klungkung and Dawan. The aim of the research was to know the production of rice straw waste and the potential of wasted organic fertilizer in intensive rice cultivation. Based on the results obtained the production of dried straw waste in each harvest about 10.21 tons/ha. Farmers do not utilize rice straw as compost by reason, not knowing how to composting. There were 30.34% of farmers who burn straw because based on the knowledge gained burn is an easy way to restore rice straw to the ground. The impact of burning rice straw was around 5,887,086 - 7,888.7 tons of organic fertilizer wasted.

Efficacy of rice straw mulch for the sustainable production and insect pest management in okra (Abelmoschus esculentus)

With an aim to utilize rice straw for crop mulching purpose and prevent environmental damage caused due to its burning, the efficacy of rice straw mulching was compared with the standard practice of silver colored polyethylene mulch and without mulch in okra (Abelmoschus esculentus (L.) Moench) for the crop growth, yield and for the reduction of insect pest population. The trials were performed during the rabi season with two sprays each of neem (Agroneem®@ 2 ml/l), imidacloprid (Confidor®@ 0.5 ml/l) and their combination. Plant growth and yield was significantly higher in silver mulch and straw mulch compared to the control. The yield of okra was maximum in silver colored polythene mulch along with the application of insecticide imidacloprid. The yield were 23.89, 16.08 and 15.80 t/ha respectively during the years, 2015-16, 2016-17 and 2017-18. The yield observed in straw mulch was slightly lower than silver colored polythene mulch, but higher than control. The straw mulch was found at par with silver colored polythene mulch in reducing population of sap sucking insect, pests, aphids, thrips, leafhoppers and whiteflies. Among the treatments, spray of imidacloprid (@ 0.5 ml/l) was found best for reducing pest population. The results indicated the utility of rice straw mulching as an organic option for the okra cultivation, which is otherwise burnt every year creating huge environmental problem in India

The Impact of Ammoniation Treatment on the Chemical Composition and In Vitro Digestibility of Rice Straw in Chinese Holsteins.

Simple SummaryRice straw has many essential uses as a byproduct of agriculture. As a feed source, due to low digestibility, low crude protein and minerals contents, the pretreatment of rice straw is required before use in ruminant feeding. To enhance the nutritive value of rice straw, different methods are practiced. Among them, treatment with ammoniation might be effective regarding the rice straw intake, enhancement of straw digestibility and crude protein levels, which are essential for enhancing the productive ability of dairy cattle. In the current study, we experimentally proved the efficiency of ammoniation treatment to enhance the different feed value parameters (dry matter digestibility, neutral detergent fiber, crude protein, gas production, acetic acid, butyric acid, and total volatile fatty acid) of rice straw.The current study was conducted to explore the ammoniation treatment effects on the chemical composition and in vitro digestibility of rice straw in Chinese Holsteins. For this purpose, rice straw was stored in polyethylene bags (35 × 25 cm, 350 g per bag) including (i) no additives (RS); (ii) 5% urea (5U, dry matter (DM) basis); (iii) 9% corn steep liquor + 5% urea (9C5U, DM basis); (iv) 9C2.5U; and (v) 9C2.5U + 3% molasses (9C2.5U3M, DM basis). The air-dry matter of the mixture was kept at the same level at 55% for all treatments. Fifteen bags (5 treatments × 3 repeats) were prepared and stored at ambient temperature (25 ± 3 °C). The chemical composition and in vitro digestibility were measured at day 60 after storage. Our analysis revealed that all the four ammoniation treatments improved the in vitro DM and neutral detergent fiber (IVNDFD) digestibility. In addition, all the four ammoniation treatments significantly (P < 0.001) increased the levels of crude protein (CP), gas production (GP), acetic acid (AA), butyric acid (BA) and total volatile fatty acid (TVFA) contents of the rice straw and decreased the neutral detergent fiber (NDF) and acid detergent fiber (ADF) of the rice straw compared to the control. Within four treated groups, the 9C5U treatment was most effective. Finally, we concluded that ammoniation treatments increased the nutritive value of rice straw. In addition the 9C5U treatment could be an effective ammoniation treatment for the better utilization of rice straw.

Sustainable utilization of rice straw to mitigate climate change: A bioenergy approach

With the growing population, agriculture productivity is increasing due to the high demand for food, which in turn produces a large amount of agricultural waste. Pyrolysis of crop residues is one of the suitable options to produce biochar and can be utilized as a fuel. In the present study, the slow pyrolysis of rice straw was carried out at four temperatures, 300 °C, 400 °C, 500 °C, and 600 °C. It was observed that biochar yield decreases (57.87–35.63%) with an increase in the process temperature. The physiochemical properties such as fixed carbon (43.91–57.63%), heating value (16.59–19.69 MJ/kg), carbon (63.77–85.13%) in biochar increases with temperature. Burning of rice straw (3Mt/year) emits the greenhouse gas (GHG) emission of about 10,953 (CO2e) Gg/year, while the combustion of biochar produced from rice straw at different temperatures emits the emission in the range of 2131–3239 (CO2e) Gg/year. The electricity generation potential analysis for produced biochars was carried out with two different power plant efficiency 25 and 30%. The electricity potential for power plant efficiency 25% and 30% was observed in the range of 1.2–1.82 TWh and 1.44–2.18 TWh, respectively.

Bioconversion of waste generated during ethanol production into value-added products for sustainable utilization of rice straw

During bioconversion of rice straw into ethanol, large amount waste water containing various organic compounds is discharged. The aim of this study was to accomplish bioconversion of phenolic acids (PAs) in waste water generated during ethanol production from rice straw into value-added products (4-vinylguaiacol (4-VG) and 4-vinylphenol (4-VP)) to make the process more ecofriendly and reduce ethanol production costs. While PAs at concentration lower than 0.4 g/L could be converted into 4-VG and 4-VP, higher PAs concentration caused PAs stress in B. subtilis. Under PAs stress, soluble polysaccharides (SPs) increased intracellular ATP and decreased H2O2 by enhancing extracellular matrices formation. At 0.8 g/L PAs, B. subtilis with SPs rapidly converted PAs into 4-VG and 4-VP at the rates of 99.64 % and 51.72 %, respectively. These results indicated that SPs facilitated conversion of waste into value-added products, achieving sustainable utilization of rice straw.

The Utilization of Rice Straw for Increase Orange Productivity and Reducing Environmental Pollution

Siam Banjar oranges was one of the leading commodities in South Kalimantan with an area 2,594 ha, 113,-149 tons of production and 43.72 ha-1 of productivity (Department of Agriculture South Kalimantan, 2006 in www.kalselprov.go.id/). The development of Siam Banjar oranges in South Kalimantan was overflow in Barito Kuala and Banjar District. The level of responsiveness plants for fertilization encourages farmers to apply high inorganic fertilizers. If it is applied continuously and without return organic matter into the soil, it will produce the reduced soil fertility in terms of chemical, physical, and biological soil. This research showed the effect of the use of straw in increasing the production of Siam Banjar oranges. First, they completely decomposed so that increasing soil fertility. Second, reduce environmental pollution because it did not leave residues as inorganic fertilizers. Third, prevent soil erosion so that nutrients needed by oranges for grow properly could be fulfilled optimally. So, oranges did not easily attacked by pests and diseases then provide abundant harvest. The results of the differences between two values ​​could be concluded that, the benefits of orange farming was produced with straw was greater than farming without straw. Revenue Cost Ratio (RCR) value of orange farming with straw was 3.56 and the Revenue Cost Ratio (RCR) value of orange farming without straw was 3.26. Based on the RCR value, orange farming with straw was more feasible than orange farming without a straw.

Simulating the effects of soil temperature and soil moisture on CO2 and CH4 emissions in rice straw-enriched paddy soil

Paddy soil from a site in northeast China was incubated with 13C-labeled rice straw in a laboratory study, and the effects of soil temperature and moisture on CO2 and CH4 emissions were measured using stable isotope ratio mass spectrometry. Aerobic incubation experiments were conducted at three soil temperatures (−10 °C, 0 °C, and 10 °C) and two soil moistures (60% and 100% water-filled pore space (WFPS)) in a laboratory for 24 weeks to simulate the rice-fallow season. An anaerobic incubation experiment was carried out for 16 weeks under a soil temperature of 25 °C and a 1 cm submerged layer to simulate the rice-growing season. Our results showed that increases in both soil temperature and soil moisture significantly promoted the cumulative CO2 emissions from rice straw during aerobic incubation. Furthermore, during anaerobic incubation, the cumulative emissions of CO2 and CH4 from rice straw decreased with increasing aerobic incubation soil temperature and soil moisture. The CO2 and CH4 emission ratios from rice straw throughout the incubation duration ranged from 6.6–15.7% and 0.0–3.0%, respectively. The addition of rice straw promoted a priming effect on native soil organic carbon (SOC) mineralization and produced CO2 emissions, which positively impacted priming during the aerobic (rice-fallow season) and anaerobic incubation (rice-growing season). The positive priming effect of rice straw on the CO2 emission duration ranged from 75.0% to 274.3% by the end of the 40-week incubation period. Furthermore, the aforementioned effect first increased and then decreased as the aerobic incubation soil temperature increased, with the greatest effect at 0 °C and lowest at 10 °C. These results suggest that high temperature during the rice-fallow season promotes the decomposition of rice straw C and leads to a decreased positive priming effect on native SOC during the rice-fallow and rice-growing seasons under the seasonal conditions of northeast China, and that it also leads to decreased CH4 production during the rice-growing season. These results have scientific significance for rational utilization of rice straw and mitigation of greenhouse effect in northeast China.

Utilization of rice straw and tea composts for strawberry and tomato production

The use of agricultural waste is of great interest to sustainable agriculture. An investigation was carried out to evaluate the effects of compost and compost tea made from agricultural waste rice straw on the yield and quality of two horticultural crops strawberry and tomato. In strawberry experiment, six treatments were considered which wereT1: 100% soil (as a control), T2: 80% soil + 20% compost, T3: 60% soil + 40% compost, T4: 40% soil + 60% compost, T5: 20% soil + 80% compost &amp; T6: 100% compost. Results revealed that number of fruit, fruit yield and total sugar (%)was increased with the increasing level of compost up to 80% after that decreased at 100% compost. The treatment T5: 20% soil + 80% compost gave the best results among the treatments to grow strawberry with good yield (185.3 g/plant) and sweetness (total sugar 5.19%). On the other hand, six treatments i.e. T1: Control, T2: Compost (5 t/ha), T3: Compost tea (50% concentration), T4: Compost (5 t/ha) + Compost tea (50% concentration), T5: Compost tea (100% concentration) and T6: Compost (5t/ha) + Compost tea (100% concentration) were considered in tomato experiment. As a result, it was observed that combined application of compost (5 t/ha) along with compost tea (100% conc.) (T6) gave the highest yield of tomato than not only control (T1) but also single application of compost or compost tea (T2, T3, T4&amp;T5). Level of compost tea concentration also showed significant effect on fruit yield of tomato. Comparing between treatment T4 and T6, fruit yield was found higher (1027.67 g/plant) in treatment T6: Compost (5t/ha) + Compost tea (100% conc.) than 961.3 g/plant in T4: Compost (5 t/ha) + Compost tea (50% conc.). So, it could be summarized that use of rice straw as compost and compost tea affects positively both in two experiments. The results of this study confirm the beneficial effects of compost to increase the yield and sweetness of strawberry and combination of compost and compost tea to increase the yield of tomato.&#x0D; Progressive Agriculture 30 (4): 335-343, 2019

Review on anaerobic digestion of rice straw for biogas production.

India is an agrarian country producing a large amount of rice straw as an agricultural residue. These residues are burnt openly leading to severe environmental pollution and health hazards. Among several options available, anaerobic digestion of rice straw into biomethane gas and digestate is a promising technology. The current paper reviews the characteristics, principles of rice straw and the process variables (temperature, volatile fatty acids, and pH, carbon to nitrogen ratio, metal elements and organic loading rate) that affect the performance of the rice straw digestion and process strategies which may alleviate the barriers and may improve the biomethane yield. Co-digestion of rice straw with nitrogen-rich substrates is proven to be an effective way to balance the carbon to nitrogen ratio, in turn, leads to nutrient balance and enhance the biomethane yields of anaerobic co-digestion system. Moreover, pretreatment is another effective strategy; physical, chemical and biological pretreatments are reviewed in the article which improved the performance of digester. The utilisation of rice straw along with other co-substrates and appropriate pretreatment may be a recommended sustainable solution for preventing environmental and health hazards.

PENERAPAN TEKNOLOGI AMONIASI JERAMI SEBAGAI PAKAN ALTERNATIF SAPI POTONG DI KENAGARIAN SUNGAI KUNYIT, SOLOK SELATAN

The feed is an essential requirement in cattle farming. The need for cattle feed reaches 80% of the cost of raising livestock. To reduce the cost of this feed, we need an alternative feed at a low price. Ammonia straw is one way to process agricultural waste products into alternative feed used for beef cattle feed. This ammonia feed technology is an efficient method for improving the quality of straw as animal feed. The objectives of this activity are 1. to increase the knowledge and understanding of cattle breeders in the use of straw waste as an alternative feed for cattle for feed cost efficiency, 2. to increase the productivity of cattle through straw ammonia feed technology, and 3. to increase the welfare of breeders by utilizing rice straw waste as feed. Livestock. The method used in this activity is counseling, demonstration of straw ammonia, and evaluating the application of straw ammonia technology as an alternative feed source for breeders. The extension method is carried out by giving lectures on the use and processing of straw waste as animal feed. Meanwhile, a demonstration of processing straw waste as ammoniated feed. The targets of this activity are farmers and the community in Kenagarian Sungai Kunyit. The results obtained from this activity, activity participants can gain knowledge and understanding in processing ammonia feed as an alternative feed. The use of ammonia feed can overcome the shortage of animal feed in the dry season/famine, overcoming environmental pollution from agricultural waste/straw. Ammoniated straw feed can also increase the digestibility of livestock so that it can increase livestock productivity. Cattle farmers in Kenagarian Sungai Kunyit can make their straw ammonia feed. Ammoniated feed can reduce feed costs, and livestock is more profitable.

Sustainable management of land, water, and fertilizer for rice production considering footprint family assessment in a random environment

Effective management of land, water, and fertilizer resources for rice production is critical for efficient and sustainable agriculture but is challenging due to the uncertainties associated the resources. The aim of this study is to propose a unified model for simultaneously optimizing crop planting area, irrigation water, and nitrogen fertilizer considering uncertainty. Water, carbon, energy, and ecological footprints are analyzed to jointly evaluate the re-allocation of resource. The proposed model has an advantage in addressing trade-offs of land, water, and fertilizer resources for different irrigation subareas in a cost-efficient, resources-efficient, and environmental-friendly manner, thus helping decision makers track resource utilization and where effort should be made from different perspectives, and also dealing with non-linearity and uncertainty. The model is applied to an irrigation district in northeast China. Results demonstrate that rice production is based on the simultaneous allocation of land, water, and fertilizer resources, but the objectives for the optimization model are conflicting. The model performs best when both water supply and precipitation are at their medium level. Compared with status quo, the value of irrigation water use efficiency increases by 1.6%, and the value of Global warming potential deceases by 7.45%. The allocation of 1.596 × 107 m3 of water can be regarded as a reference amount for water planning, which is obtained by considering possible scenarios of high-low flow level combinations of water supply and precipitation. Results of “footprint family” assessment suggest that improving the efficiency of nitrogen fertilizer utilization is particularly important to reduce greenhouse gas emissions and energy consumption, and indicate that land re-allocation helps improve the utilization of rice straw. The proposed model can help manage agricultural land, water, and fertilizer resources in a sustainable way in a changing environment, and is applicable for similar agriculture-centered regions.

Analysis of microbial utilization of rice straw in paddy soil using a DNA‐SIP approach

AbstractConsidering the close connection between soil microorganisms with carbon (C) cycling, the aim of this study was to identify the specific bacterial and fungal microbes that assimilate 13C from incorporated rice straw and explore their dynamics and characteristics during straw decomposition in paddy soil. Soil microcosms based on 12/13C‐labeled rice straw were incubated with the determination of CO2 production at 1, 3, 7, 14, 28, 56 and 90 days after straw incorporation. Meanwhile, the targeted soil bacterial and fungal communities were characterized using a DNA‐based stable isotope probing (DNA‐SIP) approach combined with Illumina MiSeq sequencing. Rice straw decomposed rapidly in the first 2 weeks, coupled with a large turnover of soil native organic matter. During this process, Actinobacteria including the orders Streptomycetales, Caternulisporales and Corynebacteriales dominated the community utilizing rice straw‐derived C with a succession from Streptomyces, to Kitasatospora, to Catenulispora. At Days 56 to 90, the dominant orders assimilating rice straw‐derived 13C were Micrococcales, Sphingobacteriia, Gammaproteobacteria from phyla Actinobacteria, Bacteroidetes and Proteobacteria, respectively. The fungal orders Onygenales, Capnodiales, Sordariales and Pleosporales showed stronger ability of 13C utilization at late decomposition stage. Taken together, along with stimulation of soil organic matter mineralization after rice straw addition, dynamics of 13C‐assimilating bacterial and fungal groups with various characteristics were identified.

Degradation enhancement of rice straw by co-culture of Phanerochaete chrysosporium and Trichoderma viride

Straw is one of the most abundant stock of renewable biomass from crop production. However, its utilization efficiency is still very low. Although co-cultivation of fungi increases the degrading rate, the co-cultivation condition needs to be optimized. To optimize the co-culture condition of Phanerochaete chrysosporium and Trichoderma viride degrading rice straw, we first tested the antagonistic characteristic between the fungi. The results showed that the best co-culture pattern was to first inoculate P. chrysosporium and culture for 4 days, then inoculate T. viride, and co-culture the two fungi for 4 days. The optimum fermentation condition was 14% (w/v) of inoculum concentration, the equivalent inoculation of the fungi, culture temperature at 30 °C, and 1:1.4 for solid-liquid ratio. Under the optimum condition, the degradation ratios of lignin and cellulose were 26.38% and 33.29%, respectively; the soluble carbon content in the culture product was 23.07% (w/v). The results would provide important reference information for the efficient utilization of rice straw to produce more accessible energy resources, such as ethanol and glucose.

Utilization of rice straw and used paper for the recycle papermaking

Rice Straw is one of the most important materials that has been used for pulp and paper production due to its abundance and cost-effectiveness. However, the pulping and papermaking characteristics of the mixture of rice straw and used paper have rarely been investigated. In this experiment, delignified rice straw was mixed with used paper in order to make recycle papers with acceptable properties. Soda pulping process was carried out to remove out of lignin. The delignification was designed to measure the effects in terms of sodium hydroxide concentration and temperature, on the cellulose and lignin content of rice straw, and its tensile strength and water absorption. The mass ratio of used paper and rice straw was varied and its physical properties was observed and compared to paper from natural rice straw. The delignification was conducted using NaOH concentrations (4-10% w/w) and temperatures (60-90°C) for 1 hour. The ratio of rice straw to used paper was varied (1:1-1:9). An optimum condition was obtained from rice straw delignification at NaOH concentration of 8% and temperature of 90°C. The results of the optimum condition obtained the highest amount of cellulose content and tensile strength while having the lowest amount of lignin content and water absorption.

Simultaneous production of cellulase and ferulic acid esterase by Penicillium decumbens with rice straw as the sole carbon source

As well as cellulose and hemicelluloses, rice straw contains phenolic acids. The simultaneous production of monosaccharides and phenolic acids could improve the value of rice straw. In this study, it was confirmed that Penicillium decumbens produces more ferulic acid esterase (FAE) than other cellulase-producing fungi. Cellulose, destarched wheat bran (DSWB), and rice straw were used as carbon sources. Little phenolic acid was released by cellulose- and DSWB-based enzymes during the saccharification of rice straw, whereas rice straw was a favorable carbon source for the simultaneous production of cellulase and FAE. High-performance liquid chromatography showed that during enzyme production, phenolic acids were released from rice straw, and ball-milling affected this release of phenolic acids. Small amounts of phenolic acids induced FAE production. Although the enzymes produced with rice straw showed lower FAE activity than those produced with DSWB, phenolic acids were produced efficiently during the saccharification of rice straw in response to the synergistic effects of cellulase and FAE. Therefore, we suggest that the production of enzymes by P.decumbens on rice straw as the sole carbon source will allow the production of more valuable products from rice straw, making the utilization of rice straw more economic.

An integrated strategy for the utilization of rice straw: Production of plant growth promoter followed by ethanol fermentation

The aim of this study was to investigate the effects of bioactives derived from rice straw on tomato growth and develop an integrated process for utilization of straw. The humic substances (HS) was obtained from rice straw in this study. To investigate the effect of HS on tomato growth, tomato seedlings were sprayed with HS and the changes in morphology were measured. Compared with the control, the relative stem heights and leaf numbers of the tomato plants increased by 17.05% and 23.47% for polyphenols in HS and by 28.27% and 17.66% for polysaccharides in HS, respectively. Moreover, the inhibition of HS on cellulase activity and ethanol fermentation were confirmed in this study. When HS was added, the activities of FPase, CMCase and β-glucosidase decreased by 37.29%, 11.54% and 30.70%, respectively. Essentially, the production of HS could be considered as a removal step prior to the bioconversion of the straw into ethanol, and it increased the productivity of ethanol fermentation by 29.39%. The findings demonstrated that HS from rice straw could be successfully used as an environmentally friendly product to increase plant yield and, the residue after HS removal exhibited an improved efficiency of bioconversion to ethanol, making biofuels more attractive.

Dual substrate fermentation strategy utilizing rice straw hydrolysate and crude glycerol for liquid biofuel production by Clostridium sporogenes NCIM 2918

The present study demonstrates a cost-effective process for liquid biofuel production (butanol and ethanol) from non-acetone forming strain C. sporogenes NCIM 2918. The cost-effectiveness was achieved by culturing the organism on cheaper raw materials such as sugar hydrolysate from lignocellulosic biomass and crude glycerol, a waste from the biodiesel industry. Three types of biomass namely rice straw, sugarcane bagasse, and areca nut husk were explored. The maximum amount of glucose was obtained from hydrolysis of rice straw and optimization of enzymatic hydrolysis conditions was carried out for the same. The hydrolysate thus obtained was used to replace pure glucose in dual substrate blend while pure glycerol was replaced with hexane washed crude glycerol. Batch fermentation resulted in a total alcohol titer and productivity of 23.5 g L−1 and 0.52 g L−1 h−1 respectively. An improvement in total alcohol titer (26.4 g L−1) and productivity (0.69 g L−1 h−1) was observed when batch fermentation was coupled with an in situ product recovery via gas stripping. To extend the cultivation period, the mode of fermentation was changed from batch to fed-batch. Fed-batch fermentation, with intermittent feeding of sugar hydrolysate and crude glycerol, coupled with gas stripping resulted in improved total alcohol titer of 44.4 g L−1 (butanol 21.5 g L−1 and ethanol 22.9 g L−1) with a productivity and yield of 0.62 g L−1 h−1 and 0.37 alcohol per gram of sugar (glucose + glycerol) respectively.