32sustainable ethanol production in vietnam

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Sustainable ethanol production in Vietnam: Current status and proposed solutions

VoThiHanh, Le ThiBich Phuong, Le Tan Hung

Institute of Tropical Biology, Vietnam Academy of Science and Technology

Abstracts:

The ethanol production in Vietnam has increased significantly since 2006. There is an

urgent need to have solutions to ensure sustainable bio-ethanol production in Vietnam.

Production and utilization of renewable energy sources should be set as a national priority with

suitable financial and scientific policies. These may include giving tax incentives to research and

businesses related to ethanol production, and development of superior sugar cane and cassava

straits suitable to specific types of soils and climate of each region. Long term planning for

material supplying areasfor ethanol production should be prepared and implemented. Specific

emphasis by appropriate funding is given to studies related to the use of agricultural waste

products such as bagasse, rice straw, husks, coffee shells, cashew fruit, cashew skin and seaweed

for the production of ethanol and value added bio-products to achieve significantly improved

economics and environment pollution control. Scientist training is critical for handling modern

techniques and equipments. Strengthen international cooperation in sciences and technologies in

the field of ethanol production would be essential.

1. Overview

Currently, plants producing ethanol from traditional carbon sources such as sugarcanemolasses or sliced cassava in Vietnam have faced many difficulties due to 1) Low productivity:4.5 kg of molasses or 3 kg of sliced cassava is needed to produce a litre ethanol (NhanQuoc

Dung, pers. comm.); 2) Prices of these carbon sources are unstable due to weather and low plantproductivity. Based on 2011 prices including 2,800 VND/ kgsugarcane molasses and 6,000VND/kg sliced cassava, ethanol producers hardly make profit with 15,000 VND/litre of ethanol(pers. obsev.); and 3) Environment concerns when tougher legal enforcement is implemented.The ratio of wastewater discharged in distiller to ethanol is 9:1 (v/v) (Le Minh Thien, pers.comm.). Several ethanol plants in Ho Chi Minh City and many provinces had to stop theirproduction because wastewater treatment does not meet the legal requirements.

We should find suitable and effective solutions to address these problems to advanceethanol production, increase economic efficiency and minimize environmental pollution.

2. The status

2.1. Production of ethanol from sugarcane molassesSugarcane molasses is a red brown liquid by-product of sugar extraction which contains

about 40-45% sugar, some minerals, metals, vitamins, amino acids, organic acids and gel mass(ref.). Vietnam has about 40 sugar factories with an output of 0.9 to 1.1 million tons of finishedsugar and 2 million tons of sugarcane molasses (ref. 2010/2011 data).About 15% of thesugarcane molasses amount is used to produce 76 million litres of ethanol (60 thousand tons) peryear (ref.). This is an expensive sugar source for ethanol production since it is also used forproduction of products of higher values such as glutamate sodium and Bakers yeast.


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2.2. Production of ethanol from cassava

In Vietnam, cassava is ranked the second crop after rice with an estimate of 8.5 milliontons output in 2010 (Report Sep 13, 2011), ranking fourth in the world. Most of cassava is usedto produce tapioca and, in a smaller extent, dried sliced cassava (up to 80% starch, w/w) used forthe production of animal feeds or ethanol. However, it is uneconomical to produce ethanol from

sliced cassava in small scales due to low productivity, especially when prices of material andproduct fluctuated significantly.

Since 2008, four large-scale ethanol producing plants from cassava with the capacity of100,000 litres/day have been invested in Vietnam (the average capital investment US$ 80-100million/each). The first one went to operation in October 2009 is Green Field of the Quang NamJoint Stock Company. Although the plant has a wastewater treatment system, it recently sufferedfrom the failure to treat wastewater as required by regulations and had to stop its production fortwo months. The other three plants owned by a joint venture between Petro Vietnam Companyand foreign companies in Binh Phuoc, Quang Ngai, Phu Tho provinces are planned to start theirproduction in the earliest of 2012.

2.3. Production of ethanol from cassava wasteA tapioca factory with the capacity of 200 tons of cassava tubers per day would discharge

about 100 tons of cassava waste (80% water) (ref.). The waste is usually dried in the sun beforebeing used as raw material to produce animal feeds. The process is prone fungal and bacterialcontaminations, posing the thread of aflatoxin production as well as environmental pollution tothe air and ground water. Cassava waste has not been used in ethanol production in Vietnam.

The laboratory of Applied Microbiology, Institute of Tropical Biology has studies ethanolproduction using cassava waste. A pretreatment method of cassava waste using acid andenzymatic hydrolyses for converting residual carbohydrates into fermentable sugars wasinvestigated. Wet cassava waste was hydrolyzed by 0.25-0.4% hydrochloric acid (HCl) at 121 oC

for 30 minutes or 0.05% Termamyl at pH 5.5, 90o

C for 1 hour, followed by the treatment with0.05% Celluclast and 0.01% AMG at pH 4.5 and 55 oC for 16 hours. One litre of hydrolysatecontaining 9% (w/v) reduced sugar solution was obtained from 1 kg wet waste. The ethanolfermentation procedure was performed from the hydrolysate supplemented with sugarcanemolasses (Final 14.5% reduced sugar) using Saccharomyces cerevisiae SC6 in 1 L scale in1.5litre flasks. After 60 hours, 7.3% (v/v) ethanol was obtained corresponding to a 50% yield. Inaddition, the solid residue after the saccharification can be used to produce a bio-product (pH3.5, 80% moisture) containing useful microorganisms (Lactic acid bacteria 108 CFU/g,Bacillus spp. 107 CFU/g and yeasts 107 CFU/g) suitable for animal and aquaculture feeding.As the result, one litre of 94.5% ethanol and 3.5 kg of bio-products were produced from 16 kgcassava waste and 1.8 kg of molasses (unpubl. data).

2.4. Production of ethanol from rice straw

Rice straw is approximately 50% of the total weight of rice plants (Putun et al., 2004).Byweight, rice straw consist mainly cellulose and hemicelluloses (~74%), lignin (~18%), fat (~1%)and protein (~3%)(Phuong et al., 2010).Vietnam rice exportation is ranked the second in theworld. In 2010, the country rice area was over 75 million hectares with an output of 40 million(report Sep 9, 2011) tons rice and 60 million tons of rice straw. Only a small amount of ricestraw is used to produce bio-fertilizers, feed cattle, and grow mushrooms. The restis burnt on the


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field polluting the air. Therefore, the use of straw resources to produce ethanol will haveenormous significance in many aspects.

In this circumstance, the Government of Vietnam has requested technical support fromJapan International Cooperation Agency(JICA) to use agricultural wastes to create energyresources. The five year project Sustainable Integration of Local Agriculture and Biomass

Industries (2009-2014) has been performed mainly by the Institute of Industrial Research of theUniversity of Tokyo, the University of Technology of Ho Chi Minh City (HCMUT) and Instituteof Tropical Biology of Ho Chi Minh City (ITB). The project aims to develop a small-scale bio-refinery process in which bio-based materials are used to produce bio-fuel for local consumption.After 2 years (2009-2011) HCMUT and ITB have been supplied equipments and trained foryoung scientists by JICA. Studying on screening and isolation of thermophilic cellulolyticanaerobes by ITB group and development of biological pretreatment of rice straw by HCMUTgroup.

2.5. Production of ethanol from seaweed

Vietnam has an extensive fresh water network and a coastline of 3200 km with potential

to grow, in a large scale of diverse species of seaweed (potentially up to 1000 species). 639species of seaweed in Vietnam have been identified including 269 species of Rhodophyta (269species), Phaeophyta (143), Chlorophyta (151) and Cyanophyta (76) (Nguyen and Huynh, 1993;Pham 1969).

So far, only small amount of seaweeds have been utilized for food, animal feed, materialindustry, traditional medicines, and biofertilizers. Recently, a project for producing biofuelsusing seaweed has been carried out by the Institute of Tropical Biology funded by theGovernment of the Netherlands (2010-2012). The research team selects Enteromorpha seaweedto produce ethanol since it grows naturally in the brackish water pond and extensive canals in theMekong Delta region. The field results showed mud seaweed biomass in ponds is 6,430 to19,056 kg per ha. Preliminary results of analysis of biochemical components that seaweed has a

high carbohydrate content (20-25% of fresh weight). Conditions for material hydrolysis andsubsequent fermentation will be optimized for ethanol production.

3. Advantages and disadvantages of ethanol production in Vietnam

3.1. Advantages

Raw materials represent 70% material cost of bioenergy. Vietnam is an agriculturalcountry, a global producer of rice, cassava and sugar cane. For examples, cassava yield and totalproduction double and triple, respectively from 2000 to 2008 (8.4 to 16.9 tons/ha yield and 2 to9.4 million tons output) (Report Sep 13, 2011). Recent investment in large scale ethanolproduction plants using cassava (100,000 litres per day) and advanced technologies shouldsignificantly enhance ethanol production with improved economics. Moreover, waste dischargedfrom ethanol production can be used to produce other products such as liquid carbon dioxide,animal feed, fertilizer, and the best is biogas for electricity supply to the plant.

3.1. Disadvantages

The supply of raw materials is unstable due to the availability of agricultural land andlow yields. There are 265,000ha for sugarcane at 51.7tonsperha, less than the plan of 2010because of the decrease in sugarcane price, most farmers choose to grow cassava instead. Since2010, one third of total cassava farmers in Vietnam have lost profit due to poor soil, excessiveuse of inorganic fertilizers, fungal diseases, seed degradation, and climate change, etc. By 2012-


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2014, three additional ethanol production plants of Petro Vietnam with a capacity of 100,000litre per day each will start operating, therefore, the demand for raw materials will increasegreatly exceeding the supply. This is expected to lead to an increase in raw material prices. Inaddition, most of factories are small and use backward technologies and equipments, resulting inlow productivity. Added cost to the production of ethanol includes wastewater treatment. Among

37 sugar factories operating in Vietnam, only 10 are profitable. Modernization would requiresignificant capital investments for factories ($100 million for a factory with an output of 100,000litre/day) and raw material supply.

4. Proposed solutions for sustainable bioethanol production:

In order to develop sustainable bio-ethanol production in Vietnam, three main followingsubjects need closely considering:

4.1. Regulations & Fund:

Set the development of bio-fuel as a national priority

Have focused investment in production areas for raw materials by Ministry of Agriculture

and Rural Development in coordination with the Ministry of Industry and Trade, andMinistry of Planning and Investment

Import superior straits of sugar cane and cassava plants suitable to soil and climate of

each region, and dissemination of advanced farming methods, appropriate fertilizers, andpest control. Thailand has achieved significant results in this issue and we can learn fromthem.

Set preferential tax incentives, financial support and subsidies for farmers

4.2. Technology

The factories continue to cooperate with foreign countries with the advanced process

technologies using cassava waste, cane bagasse, rice straw, seaweed and algae to enhance

ethanol mass production. Explore additional agricultural wastes such as coffee shells, cashew fruit

Improve microorganisms, especially yeast strains for effectively hydrolyzing complex

carbon sources and fermenting diverse simple sugars to produce ethanol at high

temperatures. Construct recombinant yeast strains which can produce amylase, cellulase

and glucoamylase to utilize raw materials.

Produce other useful bio-products from the byproduct after saccharification and stilage of

ethanol distillation for use in animal feed, aquaculture and plant. That can bring

economic benefits for the factories and reduce pollution control costs.

4.3. Workforce Enhance funding in research and education for enhanced productivity and storage of raw

materials.

In the future, Vietnam should establish an Institute for Bioenergy

Train technical staff for manufacturing, installing and operating equipments/facilities for

large scale ethanol production.


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References

Report sep. 13, 2011: Production of cassava by province. General Statistics Office Of Vietnam.Available online athttp://www.gso.gov.vn/default.aspx?tabid=503&ItemID=11752.

Report sep. 9, 2011: Planted area and production of rice 2011. General Statistics Office Of

Vietnam. Available online athttp://www.gso.gov.vn/default.aspx?tabid=230&ItemID=11637.E. Putun, EsinApaydin, ErsanPutun.Rice straw as a bio-oil source via pyrolysis and steampyrolysis. Energy 29 (2004) 2171 - 2180.

Phuong, D. T., T.T.K.Hoa, V.A.Tuan. 2010. Production of bio-oil from rice straw in Vietnam.Petro times 12: 44-49.

Nguyen HD, Huynh QN (1993) Rong bien Vietnam (Marine algae of North Vietnam). Scienceand Technology publisher, Hanoi, p 364Pham HH. 1969. Rong bien Viet Nam (marine algae of South Vietnam). Trung tam Hoc lieuXuat ban, SaiGon, 559p
http://www.gso.gov.vn/default.aspx?tabid=503&ItemID=11752http://www.gso.gov.vn/default.aspx?tabid=230&ItemID=11637http://www.gso.gov.vn/default.aspx?tabid=230&ItemID=11637http://www.gso.gov.vn/default.aspx?tabid=503&ItemID=11752http://www.gso.gov.vn/default.aspx?tabid=230&ItemID=11637

32sustainable ethanol production in vietnam

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