bagasse pith based biorefinery: a practical approach andvalorization
D Ghosh1, D DasGupta1, D Agrawal 1, SK Suman1, R Khan1, DP Bangwal 2, MS Negi 2,
D Pandey3, VT Vadde3, RK jain3, S Kaul 2, D.K.Adhikari 1*
1Biotechnology Conversion Area & 2Chemical Conversion Area, Biofuels Division, CSIR-Indian Institute of Petroleum,
Dehradun-248005, India; 3Division of Chemical Recovery, Biotechnology & Lignin by-products, Central Pulp and Paper
Research Institute, Saharanpur, UP 247001, India*corresponding author; e-mail: adhikari@iip.res.in; Ph: 0135-2525933

Abstract
Lignocellulosic ethanol programme has been initiated long back by various private as well as govt. agencies around theglobe to relief any country’s crude oil demand and thereby economic dependecy. Unlike biodiesel though ethanol has certain
edges over other biofuels in terms of near drop in characteristics and technology maturation, but technol-economic feasibility
still plays pivotal role to obstract its commercialization. High process cost in terms of feedstock procurement anddepolymerization and upstream and downstream processing are major concerns of the Industries. It has been clearly
understood that as a single product ethanol can not be landed inthe market, where it should be supported with array of value
added products to reduce its cost and instead of a product lignocellulosic ethanol can only stand rather as a process in abiorefinery mode. CSIR-IIP started its ethanol programme with this concept and developed a process where a propeitory nonsachcharomyces yeast Kluyeveromyces sp. IIPE453 is used to grow on xylose rich pretreated lignocellulosic biomasshydrolysate and ferment glucose rich LCB broth at a near theroritical yield (88%) at high temperature (50oC). Unutilized
xylose stream is chanelized for calalytic conversion into furfural and leftover lignin rich biomass is gasified to generate
producer gas or electricity. Overall process has been integrated with sensitivity analyses and economic feasibility study and
we offer an end to end process for better utilization of bagasse or bagasse pith instead of co generation which can beintegrated with a sugarmill or paper industry in a biorefinery mode.
Keywords: bagasse pith, biorefinery, Kluyveromyces sp. IIPE453, high temperature fermentation, furfural

1. Introduction
Biorefinery concept is being experimented at pilot scalelevel at many parts of the globe targeting mainly
lignocellulosic bioethanol. Production of ethanol frommolasses and sugarcane juice is a more than hundredyear old Industrial practice. Unfortunately produced
ethanol as a tranportation fuel rises many questions
which makes the product socio-economically unfeasible
through out the globe. Though production of ethanol
fromnon molasses feedstock such as grain,cssava,
sugarcane juice is being practiced in many corners of theworld,but its now evident that lignocellulosic ethanol canbe only answer if world requires a contant suply of fuelethanol. Bioethanol is one of the sole products other thanbiodiesel which is having a near drop in characteristics interms of transportation biofuel. Lignocellulosic bioethanol
can definitely reduce the burden of our country’s crude oil
import. CSIR-IIP started venture into 2nd generation
bioethanol programme with an aim of developing an end
to end process by complete utilization of sugarcane
bagasse for ethanol production and further value addition[1-7]. Ultimate aim of lignocellulosic ethanol business is
to reduce process and product cost which ethanol as asingle product cannot resolve. Hence an array of value
added products have been targeted to lower down
ethanol cost. More over if the plant can be establishedalong with a sugar mill or paper mill in line withbiorefining concept transportation and supply of feed cost
would be zero. With this background our lignocellulosic
ethanol programme was integrated with CPPRI,
Saharanpur, UP and a biorefinery concept was visualized
where sugarcane bagasse pith (a waste generated bysugarcane bagasse based paper mills) was considered
as feedstock. Presently paper industries use SCB pith as
inefficient boiler fuel which has huge problem for disposal
and environmental pollution. An average 300 tpd (Tonneper day) bagasse based paper mill consumes 800 tpd
SCB and thus generates 160 tpd pith. Idea of establish abiorefinery at sugarmillor paper mill premises is to caterquick disposal of baggasse pith and thereby its value
addition where there will not be any constraince forsupply of feed from firm to factory. This work has been
carried out integrate objectives like (1) Pretreatment andsaccharification of lignocellulosic biomass; (2) Yeastbiomass generation and further fermentation of biomasshydrolysate at high temperature and (3) Value addition to
the process intermediates.

2. Materials and methodology
Lignocellulosic biomass (Sugarcane bagasse from local
sugar industry and sugarcane bagasse pith from local
paper mill) was subjected to steam and mild sulphuricacid pretreatment for recovery of xylose rich fraction and7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013)
New Delhi, India, 23-26 October 2013

further enzymatic saccharification (market availablecellulase enzyme) was optimized to recover hexose richbroth. CSIR-IIP bioethanol process is established with
our own proprietary microorganism Kluyveromyces sp.
IIPE453 (MTCC 5314), thermotolerant yeast [Fig 1],
which grows and ferment at high temperature (50oC) andunlike Saccharomyces cereviecae, it can utilize pentose
for cell biomass generation. High temperature growthand fermentation minimize the cost required for coolingof saccharified broth as well as chance of bacterial
contamination.and also increase the rate of sugar uptake
during growth and fermentation.
Excess pentose after obtaining growth ofsufficient yeast cell is channelized for catalytic
conversion for furfural production. Leftover lignocellulosic
biomass which is rich in lignin is either gasified togenerate producer gas or considered for even further
valorisation in terms of lignin purity [Fig: 2].

Fig 3:
Ethanol production in batch mode by
Klyuveromyces sp. IIPE453 in sugarcane bagassehydrolysate at 500C

Fig 4: One step conversion process of xylose to furfural

4. Conclusions
Fig 1: SEM of Kluyeveromyces sp. IIPE453 (MTCC 5314)

Overall process has been integrated with sensitivity
analyses and economic feasibility study and we offer an
end to end process for better utilization of bagasse orbagasse pith instead of co generation which can be
integrated with a sugarmill or paper industry in abiorefinery mode to obtain high value products such as
furfural, value added lignin products, electricity apart fromethanol [4].

5. Acknowledgement

Fig 2: 2nd generation bioethanol and value addition ofprocess intermediates with material balance

3. Results and Discussion
Sugarcane bagasse pith was optized for steam and diluteacid pretreatment and further enzymatic sachcharification
to extract more than 95% xylose and 80% glucose.
IIPE453 has been adapted to grow on xylose rich stream
with Yx/S ~ 0.32 and readily ferment glucose rich stream
with 88% conversion in terms of theoritical yield [12].
Yeast biomass generated on pentose stream can berecycled at least thrice and hence pentose stream wasdiverted for catalytic conversion for furfural with 40%
conversion efficiency. Unlike conventional furfuralproduction process with homogeneous acid catalysts,
CSIR-IIP furfural process is based on heterogenous
catalyst in a biphasic system which inturn facilitates easy
product recovery [4, 8 – 11]. Lignin rich leftover biomass
after enzymatic sachcharification was gasified to produce
clean energy in form of producer gas [4] or even could be
converted to electricity [Fig 3 & 4].

Authors are cordially thankful to Dr. MO Garg, Director,
CSIR-IIP to encourage this work towards completion. Dr.
RM Mathur, Director, CPPRI is also sincerely
acknowledged to provide necessary support for feed
pretreatment and saccharification.

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7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013)
New Delhi, India, 23-26 October 2013