L.S. Hong, D. Ibrahim and I.C. Omar
Abstract
The aim of this study was to explore the possibility of utilizing agrowastes effectively to convert them into fermentable sugars by the production of in situ enzyme in solid state fermentation, which agrowaste can be used as substrates for the microbial fermentation in the production of commercial viable products. To enhance the usage of abundant agrowaste generated in Malaysia a study was conducted in view of exploring the possibility of utilizing it effectively for the conversion to fermentable sugars. Agrowaste is rich of lignoselulolytic material which can serve as good substrate in solid state fermentation to produce the fermentable sugar. In this study, solid state fermentation was carried out through the flask system in lab skill. We evaluated the production of fermentable sugars by various fungal cultures namely A. niger USM AI1, A. niger II, Trichoderma sp., A. niger F4 and Phanerochaete chrysosporium via solid state fermentation system. Nine different types of lignocellulolytic materials paddy husks, coconut fibre, wood dust, coconut meal, palm kernel cake, sugarcane baggase, tapioca meal, oil palm trunk and oil palm frond were examined. The highest productivity, 57 mg of fermentable sugars per gram substrate was obtained when A. niger USM AI1 was grown on tapioca meal and the biomass of fungus showed about 1.7 mg glucosamine/g substrate. However, about 30.0 mg of fermentable sugars per gram of substrate was obtained when A. niger USM AI1 was grown on oil palm frond and the biomass of fungus showed 1.2 mg glucosamine/g substrate. Lesser yields of fermentable sugar were obtained when paddy husk, coconut fibre, wood dust, coconut meal, palm kernel cake and sugarcane bagasse were used as solid substrates, each yielding less than 6.6 mg of fermentable sugars per gram of substrate. Thus, the nature of the substrate and the suitability of fungi used in the solid state fermentation are important variable contributing to product yield of fermentable sugars in solid state fermentation and can presumably be more economical process for agrowaste utilization.
How to cite this article:
L.S. Hong, D. Ibrahim and I.C. Omar, 2011. Lignocellulolytic Materials-as a Raw Material for the Production of Fermentable Sugars via Solid State Fermentation. Asian Journal of Scientific Research, 4: 53-61.
DOI: 10.3923/ajsr.2011.53.61
URL: http://scialert.net/abstract/?doi=ajsr.2011.53.61
INTRODUCTION
Lignocellulolytic materials are abundant in nature and have great value as alternative energy sources. The compositions of this biomass vary. The major component is cellulose (35-50%), followed by hemicelluloses (20-3%) and lignin (10-25%), in addition to minor components such as proteins, oils and ash that make up the remaining fraction of lignocellulosic biomass (Sjostrom, 1981). The biodegradation and bioconversion of lignocelluloses into useful products and biological alleviation of pollution from lignocelluloses waste is an enormous environment challenge (Panagiotou et al., 2003). A great variety of fungi can degrade these macromolecules by using a battery of hydrolytic or oxidative process (Perez et al., 2002). Degradation of lignocellulosic materials to monomeric sugars through the concerted action of cellulolytic enzymes is of great importance because sugars can serve as the raw material for a number of biotechnological production processes (Juhasz et al., 2005). For example, the sugars produced can be converted to ethanol (Lawford and Rousseau, 2003), lactic acid (El-Hawary et al., 2001) and biohydrogen (Taguchi et al., 1996: Kaparaju et al., 2009).
The technique of solid state fermentation (SSF) has been used for decades to convert moist agricultural polymeric substrates, example wheat, rice, soy cassava, etc, into fermented products (Rahardjo et al., 2005). SSF is an attractive technique for enzyme production because it presents many advantages, especially for fungal cultivation (Weiland, 1988). In SSF, the productivity per reactor or fermenter volume is much higher compared with that of submerged culture (Grajek, 1987). Also, the operation cost is lower, because simple design machinery and less energy usually are required (Roche et al., 1994).
Over the past decades, enzyme-based technologies have aroused worldwide research interest. Finding economically suitable substrates has always been of particular interest. An ideal lignocellulosic substrate is cheap, easily processed with a high yield and is suitable both for hydrolysis and for production of enzyme. Production of enzymes in situ instead of inoculating with commercially available enzymes can improve the economics of a process. However, lack of report has been seen on hydrolyzing agrowaste by using the production of enzymes in situ through solid state fermentation. Thus, the objective of this study proposed to seriously explore the possibility of utilizing agrowastes effectively to convert them into fermentable sugars by the production of in situ enzyme in solid state fermentation, which agrowaste can be used as substrates for the microbial fermentation in the production of commercial viable products.
MATERIALS AND METHODS
This study was carried out in June 2006 at Industrial Biotechnology Research Laboratory, School of Biological Sciences, Universiti Sains Malaysia, Penang, Malaysia. The duration taken to conduct this work was about 6 months.
Microorganisms and culture condition: The fungi used in this study consisted of A. niger USM AI1, A. niger II, Trichoderma sp., A. nigerF4 and Phanerochaete chrysosporium which obtained from Industrial Biotechnology Research Laboratory, School of Biological Sciences, Universiti Sains Malaysia, Penang, Malaysia. The fungi were grown on potato dextrose agar (Oxoid, England) slants at 37°C until sporulation (5 days) and then were maintained at 4°C until used. The inoculum was prepared by adding 4 mL of sterile distilled water to an agar slant and adjusting the spore suspension to 1x106 spores per mL.
Substrate preparation: To be used as substrate, the lignocellulosic material (paddy husks, coconut fibre, wood dust, coconut meal, palm kernel cake, sugarcane baggase, tapioca meal, oil palm trunk and oil palm frond) was thoroughly dried and milled with grinder machine (Rong Tsong Precision Technology Corporation, Taiwan) to 1 mm particle size. Five grams of lignocellulosic material was then weighed and place into a 250 mL Erlenmeyer flask and autoclaved at 121°C for 20 min.
Solid-State Fermentation (SSF): The sterilized solid substrate was inoculated with 1.0 mL of inoculums (1x106 spores mL-1) and the moisture content was adjusted to 80% (v/w) with sterile distilled water. The contents were mixed thoroughly by using a sterile spatula and incubated at room temperature (30±2°C). Sample as a whole flasks in triplicates, were withdrawn after one week of cultivation.
Fermentable sugars extraction: The crude fermentable sugars from the fermented materials were extracted by a simple contact method. The fermented substrate was added with 100 mL distilled water. Contents were mixed by shaking for 1 h at room temperature (30±2°C) in a rotary shaker at 150 rpm. At the end of the extraction, the suspension was filtered through filter paper (Whatman No. 1, England) and the supernatant was collected and used as the crude fermentable sugar suspension for analysis.
For further details log on website :
http://scialert.net/fulltext/?doi=ajsr.2011.53.61&org=11
Abstract
The aim of this study was to explore the possibility of utilizing agrowastes effectively to convert them into fermentable sugars by the production of in situ enzyme in solid state fermentation, which agrowaste can be used as substrates for the microbial fermentation in the production of commercial viable products. To enhance the usage of abundant agrowaste generated in Malaysia a study was conducted in view of exploring the possibility of utilizing it effectively for the conversion to fermentable sugars. Agrowaste is rich of lignoselulolytic material which can serve as good substrate in solid state fermentation to produce the fermentable sugar. In this study, solid state fermentation was carried out through the flask system in lab skill. We evaluated the production of fermentable sugars by various fungal cultures namely A. niger USM AI1, A. niger II, Trichoderma sp., A. niger F4 and Phanerochaete chrysosporium via solid state fermentation system. Nine different types of lignocellulolytic materials paddy husks, coconut fibre, wood dust, coconut meal, palm kernel cake, sugarcane baggase, tapioca meal, oil palm trunk and oil palm frond were examined. The highest productivity, 57 mg of fermentable sugars per gram substrate was obtained when A. niger USM AI1 was grown on tapioca meal and the biomass of fungus showed about 1.7 mg glucosamine/g substrate. However, about 30.0 mg of fermentable sugars per gram of substrate was obtained when A. niger USM AI1 was grown on oil palm frond and the biomass of fungus showed 1.2 mg glucosamine/g substrate. Lesser yields of fermentable sugar were obtained when paddy husk, coconut fibre, wood dust, coconut meal, palm kernel cake and sugarcane bagasse were used as solid substrates, each yielding less than 6.6 mg of fermentable sugars per gram of substrate. Thus, the nature of the substrate and the suitability of fungi used in the solid state fermentation are important variable contributing to product yield of fermentable sugars in solid state fermentation and can presumably be more economical process for agrowaste utilization.
How to cite this article:
L.S. Hong, D. Ibrahim and I.C. Omar, 2011. Lignocellulolytic Materials-as a Raw Material for the Production of Fermentable Sugars via Solid State Fermentation. Asian Journal of Scientific Research, 4: 53-61.
DOI: 10.3923/ajsr.2011.53.61
URL: http://scialert.net/abstract/?doi=ajsr.2011.53.61
INTRODUCTION
Lignocellulolytic materials are abundant in nature and have great value as alternative energy sources. The compositions of this biomass vary. The major component is cellulose (35-50%), followed by hemicelluloses (20-3%) and lignin (10-25%), in addition to minor components such as proteins, oils and ash that make up the remaining fraction of lignocellulosic biomass (Sjostrom, 1981). The biodegradation and bioconversion of lignocelluloses into useful products and biological alleviation of pollution from lignocelluloses waste is an enormous environment challenge (Panagiotou et al., 2003). A great variety of fungi can degrade these macromolecules by using a battery of hydrolytic or oxidative process (Perez et al., 2002). Degradation of lignocellulosic materials to monomeric sugars through the concerted action of cellulolytic enzymes is of great importance because sugars can serve as the raw material for a number of biotechnological production processes (Juhasz et al., 2005). For example, the sugars produced can be converted to ethanol (Lawford and Rousseau, 2003), lactic acid (El-Hawary et al., 2001) and biohydrogen (Taguchi et al., 1996: Kaparaju et al., 2009).
The technique of solid state fermentation (SSF) has been used for decades to convert moist agricultural polymeric substrates, example wheat, rice, soy cassava, etc, into fermented products (Rahardjo et al., 2005). SSF is an attractive technique for enzyme production because it presents many advantages, especially for fungal cultivation (Weiland, 1988). In SSF, the productivity per reactor or fermenter volume is much higher compared with that of submerged culture (Grajek, 1987). Also, the operation cost is lower, because simple design machinery and less energy usually are required (Roche et al., 1994).
Over the past decades, enzyme-based technologies have aroused worldwide research interest. Finding economically suitable substrates has always been of particular interest. An ideal lignocellulosic substrate is cheap, easily processed with a high yield and is suitable both for hydrolysis and for production of enzyme. Production of enzymes in situ instead of inoculating with commercially available enzymes can improve the economics of a process. However, lack of report has been seen on hydrolyzing agrowaste by using the production of enzymes in situ through solid state fermentation. Thus, the objective of this study proposed to seriously explore the possibility of utilizing agrowastes effectively to convert them into fermentable sugars by the production of in situ enzyme in solid state fermentation, which agrowaste can be used as substrates for the microbial fermentation in the production of commercial viable products.
MATERIALS AND METHODS
This study was carried out in June 2006 at Industrial Biotechnology Research Laboratory, School of Biological Sciences, Universiti Sains Malaysia, Penang, Malaysia. The duration taken to conduct this work was about 6 months.
Microorganisms and culture condition: The fungi used in this study consisted of A. niger USM AI1, A. niger II, Trichoderma sp., A. nigerF4 and Phanerochaete chrysosporium which obtained from Industrial Biotechnology Research Laboratory, School of Biological Sciences, Universiti Sains Malaysia, Penang, Malaysia. The fungi were grown on potato dextrose agar (Oxoid, England) slants at 37°C until sporulation (5 days) and then were maintained at 4°C until used. The inoculum was prepared by adding 4 mL of sterile distilled water to an agar slant and adjusting the spore suspension to 1x106 spores per mL.
Substrate preparation: To be used as substrate, the lignocellulosic material (paddy husks, coconut fibre, wood dust, coconut meal, palm kernel cake, sugarcane baggase, tapioca meal, oil palm trunk and oil palm frond) was thoroughly dried and milled with grinder machine (Rong Tsong Precision Technology Corporation, Taiwan) to 1 mm particle size. Five grams of lignocellulosic material was then weighed and place into a 250 mL Erlenmeyer flask and autoclaved at 121°C for 20 min.
Solid-State Fermentation (SSF): The sterilized solid substrate was inoculated with 1.0 mL of inoculums (1x106 spores mL-1) and the moisture content was adjusted to 80% (v/w) with sterile distilled water. The contents were mixed thoroughly by using a sterile spatula and incubated at room temperature (30±2°C). Sample as a whole flasks in triplicates, were withdrawn after one week of cultivation.
Fermentable sugars extraction: The crude fermentable sugars from the fermented materials were extracted by a simple contact method. The fermented substrate was added with 100 mL distilled water. Contents were mixed by shaking for 1 h at room temperature (30±2°C) in a rotary shaker at 150 rpm. At the end of the extraction, the suspension was filtered through filter paper (Whatman No. 1, England) and the supernatant was collected and used as the crude fermentable sugar suspension for analysis.
For further details log on website :
http://scialert.net/fulltext/?doi=ajsr.2011.53.61&org=11
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