Biomass and its potential for protein and amino acids

153 Pages·2015·14.66 MB·English

Invitation
You are kindly invited to
attend the defence ceremony
of the PhD thesis entitled:
Wednesday, 27 May 2015 at 11 am
The defence will be followed
by a reception.
Your presence will be highly
appreciated.
Yessie Widya Sari
[email protected]
Paranymphs:
Jurjen Spekreijse
[email protected]
Reonaldus
[email protected]
Biomass and its potential
for protein and amino acids;
valorizing agricultural by-products

Yessie Widya Sari
Thesis committee

Promotor
Prof. Dr J.P.M. Sanders
Emeritus professor of Valorization of Plant Production Chains
Wageningen University

Co-promotor
Dr M.E. Bruins
Researcher, Wageningen UR Food and Biobased Research
Wageningen University and Research Centre

Other members
Prof. Dr M.H.M. Eppink, Wageningen University
Dr A.J. van der Goot, Wageningen University
Dr B.G. Temmink, Wageningen University
Dr L.A.M. Pouvreau, Nizo Food Research, Ede

This research was conducted under the auspices of the Graduate School VLAG
(Advanced studies in Food Technology, Agrobiotechnology, Nutrition and Health
Sciences).
Biomass and its potential
for protein and amino acids;
valorizing agricultural by-products

Yessie Widya Sari

Thesis
submitted in fulfillment of the requirements for the degree of doctor
at Wageningen University
by the authority of the Rector Magnificus
Prof. Dr M.J. Kropff,
in the presence of the
Thesis Committee appointed by the Academic Board
to be defended in public
on Wednesday 27 May 2015
at 11 a.m. in the Aula.
Yessie Widya Sari
Biomass and its potential for protein and amino acids;
valorizing agricultural by-products
152 pages

PhD thesis, Wageningen University, Wageningen, NL (2015)
With references, with summaries in Dutch and English.

ISBN: 978-94-6257-318-5
Table of Content

Chapter 1
Introduction .......................................................................................................... 1

Chapter 2
Towards plant protein refinery: review on protein extraction using alkali
and potential enzyme assistance .......................................................................... 21

Chapter 3
How biomass composition determines protein extractability ................................ 55

Chapter 4
Enzyme assisted protein extraction from rapeseed, soybean, and
microalgae meals ................................................................................................ 73

Chapter 5
Glutamic acid production from wheat by-products using enzymatic and
acid hydrolysis .................................................................................................... 87

Chapter 6
General Discussion ........................................................................................... 103

Appendix
Supplementary Information to Chapter 6 ........................................................... 121

Summary .......................................................................................................... 135
Samenvatting .................................................................................................... 137
Acknowledgement ............................................................................................ 141
About the author ............................................................................................... 143
List of publications ........................................................................................... 144
Overview of completed training activities ......................................................... 145

Chapter 1
1
Introduction
1.1 Biorefinery: transition towards bio-based
products
The use of biomass for industrial products is not new. Plants have long been used for
clothes, shelter, paper, construction, adhesives, tools, and medicine [1]. With the use of
fossil fuels in the early 20th century and development of petroleum based refinery, the use
of biomass for industrial application declined. Since the late 1960s, the petroleum-based
products have widely replaced biomass-based products [2]. However, depletion of fossil
fuels, rising oil prices, and growing environmental awareness, push the attention and
policy towards a transition from fossil into bio-based products.
Transition towards bio-based products will have consequences on the demand and
processing of biomass to enable production of bio-based products, which are biofuels
(biodiesel and bioethanol), bioenergy (heat and power), and bio-based chemicals and
materials (such as succinic acid and polylactic acid) [3, 4]. It is important to develop
and combine various feedstock, conversion techniques, and production routes. The
integrated process of separating and converting biomass elements is known as
biorefinery.
Biorefining biomass for higher value products is expected to improve the overall
productivity and efficiency of biomass utilisation. Oilseed mills are an example of
biorefinery that is already available nowadays. Here, a combination of food and feed
products is produced. Aiming at 10% replacement of fossil fuel with biofuel in 2020 [5],
more biorefinery facilities will be set up. Production of value-added products from
residues can then serve as economic driver for low-cost biofuel production. To guide
future developments on bio-based products, a road map on the biorefinery for bulk
chemicals, known as top twelve chemicals derived from biomass, has been developed by
PNN/NREL (Pacific Northwest National/National Renewable Energy Laboratory) [6].
The target of this roadmap is to produce value-added products from carbohydrates that
can substitute petrochemical-based products. Examples of carbohydrate-based products
are glycerol, succinic acid, hydroxypropionate, furfural, and sorbitol, which are building
blocks for several products that are currently produced via the petrochemical route.

1
Figure 1. Biomass as feedstock of protein-derived bulk chemicals: more energy efficient
[7].
Protein can be used to produce nitrogen-containing chemicals by taking advantage
of the presence of the amine group (-NH ) (Fig. 1). In petroleum-based conversion of
2
crude oil into chemicals, co-reagents such as ammonia have to be used, and various
process steps are involved. With the amine in protein, various co-reagent introducing
process steps can be by-passed. With this biorefinery approach, less enthalpy is required
compared to the petrochemical route to chemical products (Fig. 1). Section 1.4 discusses
the details on how protein can be used as feedstock for bulk chemicals.
Biomass refinery for protein might not only be necessary for supplying feedstock
for the chemical industry, before all, it is important to meet the world protein demand for
food and feed. Section 1.2 illustrates the protein shortage in 2030 that we will encounter
with the current uses of protein in the diet of both humans and animals. The worldwide
protein production may provide this demand only if we consider the biomass refinery for
protein and use the protein product in an effective and efficient way according the specific
need of food, feed, and chemical industry.
1.2 World protein demand
The world population is currently growing with the rate of 1.14% per year
increasing current population with 80 million per year [8]. Consequently, more food is
needed. In 1992 world protein supply for food was 61 million tonnes and increased to
198 million tonnes in 2009 [9].Increase income earned by people in developing countries
also contributes to an increased demand in protein. In 2009, people living in Europe and
Asia, consumed 102 and 75 g protein/capita/day. For European people, representing those
living in developed countries, that number is not so much different with their
consumption in 1992, 98 g protein/capita/day. But for Asians, representing those living
in developing countries, that number is considerably higher than their consumption in
1992, with only 63 g protein/capita/day. In addition to this, type of diet has also shifted.
As income increases, people tend to eat more animal based protein than crop based one.
2 Introduction
The increase in animal protein in diets leads to lower direct crop protein for food, yet a
larger, indirect, increase in demand for feed.
In 2030, cereal and oilseed will be the major crop protein supplier, as in 2013
1
(Table 1). Cereal and oilseed productions in this period are predicted to be 2838 [10] and
686 million tonnes1[10, 11], respectively. Protein from these crops can be directly
consumed or indirectly in the form of animal protein products. For the latter, crop protein
is required to be fed to animal. As much as 1200 million tonnes of cereal [10] and 173
million tonnes of oilseed are allocated for feed [10, 11]. These numbers correspond to
120 and 52 million tonnes of cereal and oilseed protein, respectively. In total, 172 million
tonnes of protein from these crops are produced for feed. As people are projected to eat
more animal protein than crop protein, we assume that animal protein supplies 2/3 of
human protein demand. If total protein demand for human consumption in 2030 is 174
million tonnes2, then as much as 116 million tonnes of animal based protein is required.
Due to the inefficient conversion of crop protein into animal protein product3 [13], 696
million tonnes crop protein is required to produce 116 million tonnes of animal protein.
The worldwide cereal and oilseed protein production only supplies 25% of world demand
for feed. Shifting the human diet to more crop and less animal protein is rather an optimist
scenario. However, even with this scenario, more feed proteins are demanded than
protein produced by cereal and oilseed crops. Grass is another important crop that
supplies additional protein. However, the limited digestibility of grass, certainly from
non-cultivated grassland, limits its protein intake by ruminants. With this, the available
grass is predicted still not enough to meet the total worldwide feed protein demand. In
addition to this, residues from agro-industry are used and needed to meet the total feed
protein demand.
As much as 1406 million tonnes of cereal [10] and 68.6 million tonnes of oilseed
[10, 11] are dedicated for food. For cereal, these numbers correspond to 140.6 million
tonnes cereal protein. For oilseed, with 30% protein content, these numbers correspond
to 20.6 million tonnes oilseed protein. In total, there will be 161.2 million tonnes of
protein produced from these crops. However, only part of these cereal and oilseed
proteins can meet the human food protein demand, since certain crops have lower protein
quality than that is needed for humans. Protein Digestibility Corrected Amino Acid Score
(PDCAAS), a parameter for assessing the quality of protein for human consumption can
be used to measure the bioavailability of protein provided by crop [15]. The PDCAAS
for cereals and oilseeds used in this calculation was 50% and 80%, respectively.
Considering the PDCAAS, cereal and oilseed protein production will be 86.7 million
tonnes. After considering both protein availability in quantity and quality, assuming an
average daily uptake of 57 gram of protein per day, and assuming that people consume
1/3 their protein directly from crops, cereal and oilseed protein are enough to supply 58
million tonnes of direct crop-based protein demand. The remaining 28.7 million tonnes
can be used to supply feed demand which is still not enough to fully supply feed demand.

1 Extrapolated.
2 Assumed that recommended daily intake protein is 57.5 g protein/capita/day and world
population in 2030 is 8.3 billion people [12].
3 As much as 6 kg crop protein is required to produce 1 kg animal protein [13, 14].
3