Valorization of PKM (Palm Kernel Meal) by bioconversion

Introduction

Material and methods

Results

References

Talamond, P.1, Meryandini, A.2, Ayuningtyas, I.1, Fahmi, M.R.3, Wayan, S.3, Yamin, M.3 and Hem S.1 1) Institute de Researche pour le Développment (IRD), Wisma Anugraha, Jalan Taman Kemang 32B, Jakarta 12730, Indonesia. 2) Research center for Bioresources & Biotechnology Bogor agricultural University (IPB)3) Badan Penelitian dan Pengembangan Kelautan dan Perikanan, Pusat Penelitian dan Pengembangan Perikanan Budidaya. c/o Jalan Perikanan No. 13, Pancoran Mas, Depok.illustration by: Bambang Dwisusilo © IRD, 2011.

PKM is generated after extraction from the nut of palm oil fruits of Elaeis guineensis. The composition of PKM varies depending on their variety, growing conditions, extraction methods, storage parameters. After extraction, the large proportion of proteins (80-90%) and lipid (70-80%) are linked to the polymer ligno-cellulo-hemicellulose fraction. Fiber decreased significantly from 70% to 20-30% in PKM. The high temperature during the oil extraction process started the degradation process of the fiber in PKM and produced the modified proteins bear dicarbonyl Maillard reaction intermediates.

MESOCARPENDOCARP

KERNEL

EXOCARP

The distribution of microorganism communities was 98.6% for bacteria, whilst yeast and fungi were present in very low proportions and only amounted to 1.4% in the fermented PKM samples.

The microflora gradually changed from Gram- to be dominated by Gram+. All undesirable microorganisms present at the start of fermentation were almost eliminated after 36 h of fermentation. Fungi numbers varied between 2.3 X 106 and 4.2 X 106 after four days of fermentation. The pH decreased from 5.1 to 4.0 after 84 h. After 2 days of fermentation, the composition of the microorganism communities, that could be counted as viable, showed a majority of strains from the families Spectrococcaceae and Lactobacillaceae in aerobic and anaerobic conditions. These bacteria are involved in the synthesis reactions of lactic acid from hexose. Therefore, there is a need for research in the isolation, identification and characterization of the microorganisms involved in the fermentation of PKM to enable the selection of most suitable strains.

[1] Ng, W.K., Chong, K.K. 2002. The nutritive value of palm kernel meal and the effects of enzyme supplementation in practical diet for red hybrid tilapia (Oreochromis sp.). Asian Fisheries Science 15: 167-176[2] Hem, S., Toure, S., Sagbla, C. and Legendre, M. 2008. Bioconversion of palm kernel meal for aquaculture: Experiences from the forest region (Republic of Guinea). African journal of Biotechnology, 7, 1192-1198.

Palm kernel meal (PKM) is available in large quantity in many tropical countries, particularly in Indonesia. Data from USDA (2010) show that Indonesian palm oil production reached 23 million metric tons (mmt) in 2010 and it caused the supply of PKM to increase from 3.12 mmt in 2009 to 3.5 mmt in 2010. Of the total PKM production in Indonesia, 85% were exported. Despite the fact that Indonesia produces large amounts of PKM, this by-product is not widely used, either as food for animal production, or other purposes in Indonesia. Some researchers tried to enhance the nutritive value of PKM:

• with enzymes to digest fibers and improve bioavailability of nutrients;

• with fermented PKM with Treicoderma konigii [1];• with a bioconversion process (figure 1) with the objective

of converting nutrients from PKM into biomass of Hermetia illuscens larvae (maggots) [2].

Plant materials. PKM was provided from PT. Perkebunan Nusantara VII, Bandar Lampung (Sumatra). Mesocarp nuts of palm oil were harvested from trees cultivated in Depok (Java).Fermentation procedure. The fermentation was made by mixing 40 kg of PKM with 80 kg of water (1:2) in a drum. The samples were taken at a depth of about 40 cm from the surface using pipe. The samples were taken at 12 h intervals (0,12,24,...) during 7 days for analysis of pH, water content, D-mannose and D-glucose, acidity, organic acid, fiber, protein concentration, and microbial analysis.Proximat analysis. Sample of PKM and kernel were analyzed by the standard procedure as adopted by AOAC 9991.43 method (AOAC international 1998) for protein, lipid, ash and fiber.Bacterial enumeration. Sampling. Ten grams of fermented sample dispersed in 90 ml of NaCl 0.9% sterile, then submitted to a mechanical stirrer during 5 mins to extract cells from the substrate. This corresponds to a 10-1 dilution. The extraction step is followed by serial dilutions of the sample to separate individual reproductive units.Microbial counts. Using “pour plating technique”, the samples incubated at 30°C with isolated colonies known as Colony Forming Unit (CFU). The range of colonies acceptable for counting is 30-300 colonies on the plate.

11 - 13 May 2011, Jakarta, Indonesia.

Larva Hermetia illuscens

0

1

2

3

4

5

6

0

50000000

1E+09

1.5E+09

2E+09

2.5E+09

3E+09

3.5E+09

4E+09

4.5E+09

0 12 24 36 48 60 72 84 96 108 120 132 144 156 168

TSA

TSA an

pH

CFU

/g

Hour

Figure 2. Microbial counts during PKM fermentation

Palm Kernel Meal (PKM)

Characteristics Dry matter

Crude protein Lipid Ash Fiber

PKM (Jambi - Sumatra) 92 16 7.8 4.6 22.3

Mesocarp 89.6 3 2.1 2.1 70.9

PKM exporteda 89 18 8.3 4.5 17.5

Table 1. Proximat composition (in %), amino-acid, fatty-acid, ash and fiber contents of Palm Kernel Meal and mesocarp nut of palm

a) From GP Feeds Ltd – Animal feed manufacturer to the dairy farming industry.

PKM fermentation

Bioconversion

Objective

Figure 1. Bioconversion process by Hem et al. [2]

Insect unable to utilize plant

polymer

Role of the microorganism communities present in the fermentation process in relation to their valorization in aquaculture

Protein source in fish feed

pH